Photoselective isotope fractionation dynamics in cosmo and atmospheric chemistry

Photoselective isotope fractionation dynamics in cosmo and atmospheric chemistry | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article Photoselective isotope fractionation dynamics in cosmo and atmospheric chemistry Raphael Levine This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-5896715/v1 This work is licensed under a CC BY 4.0 License Status: Posted Version 1 posted You are reading this latest preprint version Abstract Photochemical isotope effects have been measured for nearly 50 years with the driving force being the understanding of natural processes. This has ranged from climate and atmospheric chemistry and dynamics, planetary atmospheres such as Mars, Titan and Jupiter, consequences for resolving solar system formation mechanisms, interstellar molecular clouds, solar wind and meteorites. 1,2 The distribution of isotopomers of compounds varies significantly across the solar system and beyond, invalidating the notion of a constant molecular weight. 3 Nitrogen, with two stable isotopes, exhibits wide-ranging isotope ratios that arise from different sources across the solar system. 4-11 We seek to understand variability by explicitly examining the dynamics of photodissociation. The paper integrates measurements of photodissociation of N 2 at the advanced-light-source via scavenging of the nascent N atoms and state of the art dynamics modeling, including preferential light shielding. 12-14 We show that the exceptionally high nitrogen isotopic fractionation underscores the essential role of dynamics in interpreting photoselectivity and its dominant non-statistical aspects that we establish. High level quantum chemical computations of the relevant potentials and of their different selective couplings that vary in magnitude are vital input towards our demonstrating photoselective chemistry. Beyond N 2 , our approach is equally applicable for elucidating the isotope ratio reported for CO. 15,16 The findings support planetary exploration models, including NASA's Artemis missions, where nitrogen isotopic studies of the lunar and Martian surfaces are crucial for understanding water sources and volatile chemistry. Physical Chemistry Cosmochenmistry photoselective chemistry Figures Figure 1 Figure 2 Figure 3 Introduction High precision stable isotope ratio measurements of natural samples, terrestrial and extraterrestrial, have been used over an extraordinary range of disciplines. This includes solar system origin and evolution, planetary science, greenhouse gas source identification, biogeochemistry, oceanic global primary productivity, upper atmospheric photochemistry, Mars planetary origin and evolution, tracking of the origin of life of earth, cometary composition and chemistry, interstellar molecular clouds and archaeology. Recent review is given in ref. 2 . The use of oxygen isotopes of water ice in polar regions have allowed determination of the earth’s temperature throughout the Holocene, and measurement of oceanic foraminifera to determine oceanic temperatures and ice mass over hundreds of million years. The origin dates to 1947 and a paper by Urey 17 detailing the thermodynamics of isotopically substituted molecules, 18 calculation methodology of the isotopic exchange equilibrium and the development of the isotope ratio mass spectrometer that allows the needed precision 19 . At present, an important area of applications of isotope measurement centers on the isotope effects during photodissociation 1,2 . One of the best-known applications involves a mass independent isotope effect in photodissociation of SO 2 in the earth’s earliest atmosphere between 3.8 and 2.2 billion years ago. Anomalous sulfur isotopic composition of ancient rock sulfides and sulfates provide a barometer of oxygen/ozone levels associated with history of photosynthesis in the Archean 20 . The use of stratosphere ozone formation and its associated O 2 anomaly are used to quantify global oceanic primary productivity and upper atmospheric photochemistry 1,2,21 . Photodissociation plays a particularly important role across space and time because its isotopic selectivity is potentially far higher than other factors. Modeling across relevant wavelengths and predicting isotope effects is intrinsically challenging, but needed as otherwise the fractionations must be measured across wide wavelengths which is not realistic in the UV region. In this paper we report a combined measurement/modelling effort to resolve all contributing parameters in photodissociation and their isotopic selectivity across a UV range. Molecular Nitrogen is chosen as all isotopic parameters are well known. Furthermore, it has a range of applications that have an immediate need and is relevant to other molecules and to contemporary space and planetary exploration and earth’s mesopheric chemistry and its linkage to space. Cosmo photochemistry does differ from other branches of chemistry in that it is typically a high energy density process, often at low material density. Challenges are both the theoretical description of elementary processes and of the simulation of gas flow 22 . The elementary photodissociation dynamics matter because almost always there is a maze of electronic states, see Figure 1, that are potentially relevant at the energies of interest and there is a range of coupling mechanisms of different strengths among these states 23 . Often these couplings are individually mass dependent, and their effective strength depends also on the spacings on the energies of the coupled states. As we discuss below the electronic state of the nascent products can therefore be dynamically non-statistical and show considerable isotopic selectivity. Nitrogen isotope measurements of extraterrestrial objects have been extensively used. This includes interstellar molecular clouds and proto stellar envelopes, and proto planetary disks, all driven by the photolysis of N 2 6,25 . Photolysis of nitrogen in extra-terrestrial environments is a precursor of organics observed in meteorites that have uncertain synthetic pathways 8-11 . The photochemistry of species initiates within molecular stellar outflows and processes on gas grain chemistry, planetesimals, and their record is ultimately stored in interplanetary dust grains, meteorites, and other reservoirs, such as the lunar surface 10 . The complex organic species observed in carbonaceous chondrite meteorites are potentially sources of prebiotic species. Isotopic measurements with knowledge of the isotope effects provide a way to define source processes The pervasiveness of nitrogen isotopic photochemistry extends to Titan as well 26-29 . An outcome of the present work is that it might be of use in space exploration. NASAs Artemis 2 mission is set to fly its astronaut mission around the moon in 2026 and in 2028 send astronauts to land near the moons south pole and establish the first off planet inhabitation. A part of the science of importance concerns water that might be available for the future astronaut mission to Mars. Water on Mars has been a highly complex issue as there was previously water on Mars but lost over time. In the Viking Landing, the nitrogen isotopic atmosphere has a massive 15 N enrichment 30 that was first modeled by 31 . The enrichment was suggested as arising from selective escape of 14 N vs 15 N following N 2 photolysis 32 . A quantitative measure of the enrichment is δ 15 N, the fractional excess of δ 15 N over the mean isotopic composition on earth. Recently, the Curiosity Mars rover remeasured Mars nitrogen isotopic composition at δ 15 N = 572 per mil, confirming Viking measurements 32 . As discussed, it may be due to mass-dependent escape selection, but a cometary impact could account for the enrichment as they contain high δ 15 N values, between 600 and 1000 per mil 32 . Of a similar vein as Mars, at 100 Km in the earth’s atmosphere the environment is such that there is no longer a Boltzmann distribution defining the interface of our atmosphere with space and atmospheric leakage to space occurs. Very little is known at the isotopic level to quantify the distillation. This is a significant component, and it is applicable to earth’s atmospheric evolution over time. There is expected isotopic chemistry as suggested for photoproduced atomic oxygen 28 . The only isotopic measurements of the mesosphere are from rocket borne cryogenic whole air samples where an O 2 anomaly is reported at 60 km 33 . It is expected that nitrogen will have a large fractionation due to the observed massive isotope effect and higher absorption. The new data will now allow a modeling of what to expect and guide future sampling through the mesosphere into space. Experimental The experiments were all performed at the Advanced Light Source at the Lawrence Berkeley Laboratory using the UV source available at the chemical dynamics beamline. Details are described in 34-36 . In this work, we have maximized the experimental conditions that increase yield and lower blank allowing higher precision. A complete account in the Supplementary Information, SI, includes a schematic of the experimental set up, Figure S1, as well as the new developments specific to this work and the measured isotopic fractionation as a function of energy in Table S1. Theory The implication of our theoretical work is that the intricate dynamics of the photodissociation of N 2 very much matters. It implies that the outcome is not statistical and that the isotopic fractionation does reflect the initial conditions. Photo selectivity thereby provides a probe of the environment. We further argue that our considerations apply to other molecules of astrochemical interest such as CO. We discuss the essence of the modelling and why and how it applies to other systems. A key first step is the understanding of the excited states that are accessible by a one photon transition from the electronic ground state. In N 2 and in most other examples, these are (quasi) bound states, states that do have enough energy but that do not directly dissociate 36 . Direct dissociation in N 2 requires an energy higher than 117,000 cm -1 and is typically competing with ionization. Extensive quantum chemical studies have well characterized these singlet electronic adiabatic states in N 2 , e.g., 37-42 and identified the vibronic states e.g., 37 . The bound singlet vibronic states are spin-orbit very selectively coupled 43 to a large manifold of triplet electronic states, some of which are dissociative. Both non adiabatic and spin orbit terms couple the triplet states among themselves such that eventually but not statistically, the molecule exits on a dissociative channel. The available exit channels are identified in the potential energy curves as shown in Figure 1. Several potential energy curves for the nuclear motion are highly anharmonic. The lowest exit channel can be populated from lower lying states accessed by spin orbit coupling from the lowest singlet state. We follow the quantum dynamics of the molecule from the excitation to the exit 24 , see SI. Our computations show that different initial conditions in each isotopomer can result in exits on a different channel, Figure 2. The isotopic selectivity is mainly due to that similar initial conditions for different isotopomers can result in different exit preferences. In N 2 and for other molecules such as CO, different exit channels correspond to different electronic states of the product atoms. These two complementary aspects of selectivity that we demonstrate in the computations are here suggested as a dynamical origin of the exceptionally large isotopic fractionation that is seen experimentally , Figure 2 . In the case of N 2 photodissociation experiments where the N atoms are scavenged by an excess of H 2 , we take it that N( 2 D ) atoms are more than ten times more reactive towards H 2 than N( 2 P) atoms 46-51 and in the computations we regard N( 2 P) as non-reactive. In the photodissociation of CO, Carbon can exit on different electronic states. Only O( 3 P) atoms can exit at lower energies and O( 1 D) atoms are produced at an energy above 94.12nm 52 . For N 2 the energy threshold for producing N( 2 P) atoms is slightly above 89.3 nm. Thus our approach is relevant for meteorite and radio astronomy. The observed and the computed branching into different channels as a function of the initial state and of the isotope are shown in Figure 2 above and reported in Tables S3-S7 of the SI. It is seen to change dramatically with energy, and, in our interpretation, it is the difference in the decreasing yields of the much more reactive towards H 2 N( 2 D) atoms in the two isotopomers that is the cause of the drop in the isotopic preference at the higher energies. See also Figure S3 of the SI. Results Our experiment and computations, Figure 2, consistently report an exceptionally high, thousands of per mil, isotopic fractionation in the photodissociation of N 2 with a natural isotopic composition (0.364% 15 N 14 N). It is the higher most values reported 34 . The precise number depends on the excitation energy, the composition and density of the target gas, the method of detection of products, etc.. The computations reproduce and account for the observed smooth trends and provide an understanding on the contribution of the dissociation dynamics to the high isotopic fractionation. As shown in the comparison with the experimental results in Figure 2 the modelling is consistent with both the rather large magnitude and its overall shape as a function of the excitation energy. To accurately capture the observation, we bring in dynamical considerations that show a rather non monotonic variation in the electronic states of the dissociated atoms. The computed branching fractions of the different products, Figure 2(B), are in close agreement with recent molecular beam measurements for both the lighter and separately, the heavier isotopomer 44,45,53 . Combining the branching fractions with the absorption cross section enables us to examine, as in Figure 3, the dissociation to N( 2 D) and N( 2 P) products separately for either isotopomer. Their differences suggest a very dominant role of the dynamics in governing the isotopic fractionation at higher energies. Our computed lifetimes for dissociation 23 are also quite different for different initially optically excited states (S or P symmetry) and for the two different isotopomers, see SI. It is remarkable that some initial states dissociate very slowly while others, adjacent in energy, rush to exit. There can be considerable variation of the results for different physicochemical initial conditions, such as composition and column density as determined by the shielding of the incident light. Computations show decreasing selectivity at lower pressures because of reduced self-shielding, Figure S3(D). The molecular Hydrogen present in the experiment to scavenge the nascent N atoms does not significantly absorb light in the spectral range of interest and has a limited effect in the shielding computations, Figure S3(B). The central role of dynamics requires high level quantum chemistry computations of the energetics and the non-adiabatic and the state-selective spin orbit couplings, Figures S5 and S6. Beyond astrochemistry and space physics our results of contrasting the two isotopomers are of key relevance to the long sought critical demonstration of photoselective chemistry. 54 We explain and illustrate by quantum dynamics that employ high level quantum chemical computations that there are two unique dynamical effects that do give rise to the spectacularly high measured isotopic enrichment. First, even small variations in the wavelength of the light can result in a different exit channel of the nascent products. This also results in considerable variations in the rate of dissociation as a function of excitation wave length. Second, at about the same wavelength, two different isotopomers can lead to products exiting on different channels. This is what laser people call a highly not statistical and state selective chemistry, a long-sought goal that using the isotopic preference we conclusively demonstrate that we achieved. Perspective The measured photodissociation enrichment in 15 N with wavelength with a down trend above 90 nm is seen to arise from dynamical effects. There are two effects identified by the computations, the branching between exit channels, Figure 2 and the more subtle role of the non-monotonic variation in the individual line widths that in the higher energies begin to significantly overlap. The widths have a significant effect on both the shielding computations at the higher energies and on the cross sections themselves. The modeling requires accurate quantum dynamical simulations using state of the art multireference potential energies and their state-dependent couplings. As the excitation energy increases, competition between different coupled exit channels, some leading to reactive N ( 2 D) and some leading to significantly less reactive N ( 2 P) in an isotope dependent way, modulates the selectivity for the 15 N atoms. As a result, the dissociation lifetimes of initial states close in energy vary in a nonmonotonic isotopic dependent manner as a function of energy. Our work shows that modelling can interpret the novel experimental observations and account for the exceptionally high selectivity. Additional progress requires accurate high resolution UV spectra for entire UV bands, both measured and computed to complement fractionation measurements. The complexity of the non-statistical dynamics and the role of the light shielding make such high-resolution work necessary for the detailed understanding of isotope enrichment fractions in the higher energy regime for nitrogen and also for other molecules of interest in cosmochemistry such as CO. Given the massive range in isotopic composition, the interpretation of e.g the Mars atmosphere and photolysis intersection, meteoritic nitrogen may be modeled better. Samples from the earth’s interface with space where N 2 photolysis occurs would be an interesting application. Declarations Acknowledgments: US–Israel NSF–BSF grant 2019722 (KK, NAG, RDL). Fonds National de la Recherche (F.R.S.-FNRS, Belgium), #T0205.20 (FR) This research used resources of the Advanced Light Source, which is a DOE Office of Science User Facility under contract no. DE-AC02-05CH11231. Competing interests: Authors declare that they have no competing interests. Data and materials availability: All data are available in the main text or the supplementary information. 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Additional Declarations The authors declare no competing interests. Supplementary Files N2natureJan25SI.docx Cite Share Download PDF Status: Posted Version 1 posted You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. Our growing team is made up of researchers and industry professionals working together to solve the most critical problems facing scientific publishing. Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-5896715","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":406771112,"identity":"217dd85c-c606-439c-880a-b3eaaf5a9a48","order_by":0,"name":"Raphael Levine","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA7klEQVRIiWNgGAWjYBAC+wYGNgaGCgYGNnYQg0cCLHrgAR4tBgdAKs8AtTAja0kgpIWxDcgCa4EBvFqOnz32mHfeNnk+oJbHPDIWDPztBxjx2mLfk5duzLvttmEbMwO7MQ/QYRJnEvA7zI4hx0waqIURqIVNGqSF4QYBvxjzvwFqmXPbHq5FnpAWwxkgWxpuJ8K1GBDSYnDjXZrknGO3k9uYGdsk5/BI8BieSWzAr+V87jGJNzW3bee3Nx+TeNtTJyd3/PDhDx/waAHGHgMTD5jB2MDA2APkghj4AQ8D4w845wcehaNgFIyCUTBiAQASO0UiwvqZ2QAAAABJRU5ErkJggg==","orcid":"","institution":"","correspondingAuthor":true,"prefix":"","firstName":"Raphael","middleName":"","lastName":"Levine","suffix":""}],"badges":[],"createdAt":"2025-01-24 15:14:34","currentVersionCode":1,"declarations":{"humanSubjects":false,"vertebrateSubjects":true,"conflictsOfInterestStatement":false,"humanSubjectEthicalGuidelines":false,"humanSubjectConsent":false,"humanSubjectClinicalTrial":false,"humanSubjectCaseReport":false,"vertebrateSubjectEthicalGuidelines":true},"doi":"10.21203/rs.3.rs-5896715/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-5896715/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":74900813,"identity":"f73da8ae-5f3d-4ebf-be47-59474bcd5876","added_by":"auto","created_at":"2025-01-28 07:20:51","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":129517,"visible":true,"origin":"","legend":"\u003cp\u003ePotential energy curves computed for the N\u003csub\u003e2\u003c/sub\u003e electronic states in energy range 90 000–120 000 cm\u003csup\u003e-124\u003c/sup\u003e. The black solid curve singlets are the states that can be VUV optically accessible by one photon from the ground electronic state. Triplet states are plotted as dashed lines and quintets with dotted lines. The lowest dissociative exit channels are shown in blue and orange.\u003c/p\u003e","description":"","filename":"1.png","url":"https://assets-eu.researchsquare.com/files/rs-5896715/v1/abf076dfc829785b8e3caa7e.png"},{"id":74900446,"identity":"e5336f57-9983-4f1b-9fe4-3cce25b0549b","added_by":"auto","created_at":"2025-01-28 07:12:51","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":78394,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003e(A)\u003c/strong\u003e The experimental, red dots, and computed \u003csup\u003e15\u003c/sup\u003eN enrichment factor for a model that incorporates the primary dynamical effect namely that in the shaded blue area, at energies above 112,000 cm\u003csup\u003e-1\u003c/sup\u003e, not all nascent N atoms are produced in the N(\u003csup\u003e2\u003c/sup\u003eD) electronic state, see Figure 1. The blue curve is a computation that assumes that only the N(\u003csup\u003e2\u003c/sup\u003eD) react with H\u003csub\u003e2\u003c/sub\u003e in the time during the flow and takes into account the variable width of the spectral absorption lines. As discussed in considerable detail the SI, the computed results in panel (A) above (blue line) and in Figure S3, include a spectral band-dependent line width. This lowers the computed curves in the intermediate energy region and results in a closer agreement with the experimental enrichment factor (red line) than the results shown in figure S2 that are computed with fixed width. (B) Measured (see Table S1), black circles, branching fraction of nascent N(2D) atoms for the two isotopomers \u003csup\u003e44,45\u003c/sup\u003e and the values, blue bars, computed by the dynamics. See Figure 3 for the separate cross sections to final states of the N atoms.\u003c/p\u003e","description":"","filename":"2.png","url":"https://assets-eu.researchsquare.com/files/rs-5896715/v1/cacd5264c2ce126076b52c8d.png"},{"id":74900443,"identity":"f5c04d21-8c2a-4e6e-b18b-ba9858a6bd44","added_by":"auto","created_at":"2025-01-28 07:12:51","extension":"png","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":98377,"visible":true,"origin":"","legend":"\u003cp\u003eAbsorption cross section, black and cross section to the \u003csup\u003e2\u003c/sup\u003eD state of the N atom, blue, for the two isotopomers. \u003cstrong\u003e(A)\u003c/strong\u003e Over the entire energy range measured. (B) gives an example where large isotopic shift results in overlap between \u003csup\u003e14\u003c/sup\u003eN\u003csub\u003e2\u003c/sub\u003e and \u003csup\u003e14\u003c/sup\u003eN\u003csup\u003e15\u003c/sup\u003eN bands of different nature.\u003cstrong\u003e (B)\u003c/strong\u003e and \u003cstrong\u003e(C)\u003c/strong\u003e show spectral regions where input from the dynamics is essential both due to difference in the reactivity of the nascent product and natural linewidth. To compute the isotopic fractionation the results are averaged over the fairly broad spectral profile of the ALS light beam, see figure S4 in the SI. The same computation also accounts for the decrease of the light intensity along the path length of the experiment, see figure S1. This is the shielding effect and it is included through a standard Beer-Lambert law, see details in the Section Shielding of the light beam of the SI.\u003c/p\u003e","description":"","filename":"3.png","url":"https://assets-eu.researchsquare.com/files/rs-5896715/v1/cafdcb14d0490bf6e42f69ce.png"},{"id":74902347,"identity":"3969369a-d1fd-478b-a4da-e52cae17ae2a","added_by":"auto","created_at":"2025-01-28 07:36:52","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":1443917,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-5896715/v1/62a3c10e-d595-4791-b0dc-3956f4497d3d.pdf"},{"id":74900448,"identity":"2a01e77b-8269-4204-a55a-9a1ac44c8315","added_by":"auto","created_at":"2025-01-28 07:12:51","extension":"docx","order_by":1,"title":"","display":"","copyAsset":false,"role":"supplement","size":6544106,"visible":true,"origin":"","legend":"","description":"","filename":"N2natureJan25SI.docx","url":"https://assets-eu.researchsquare.com/files/rs-5896715/v1/0e1d1084955797afc629ca98.docx"}],"financialInterests":"The authors declare no competing interests.","formattedTitle":"\u003cp\u003e\u003cstrong\u003ePhotoselective isotope fractionation dynamics in cosmo and atmospheric chemistry\u003c/strong\u003e\u003c/p\u003e","fulltext":[{"header":"Introduction","content":"\u003cp\u003eHigh precision stable isotope ratio measurements of natural samples, terrestrial and extraterrestrial, have been used over an extraordinary range of disciplines. This includes solar system origin and evolution, planetary science, greenhouse gas source identification, biogeochemistry, oceanic global primary productivity, upper atmospheric photochemistry, Mars planetary origin and evolution, tracking of the origin of life of earth, cometary composition and chemistry, interstellar molecular clouds and archaeology. Recent review is given in ref. \u003csup\u003e2\u003c/sup\u003e. \u0026nbsp;The use of oxygen isotopes of water ice in polar regions have allowed determination of the earth\u0026rsquo;s temperature throughout the Holocene, and measurement of oceanic foraminifera to determine oceanic temperatures and ice mass over hundreds of million years.\u003c/p\u003e\n\u003cp\u003eThe origin dates to 1947 and a paper by Urey\u003csup\u003e17\u003c/sup\u003e detailing the thermodynamics of isotopically substituted molecules,\u003csup\u003e18\u003c/sup\u003e calculation methodology of the isotopic exchange equilibrium and the development of the isotope ratio mass spectrometer that allows the needed precision\u003csup\u003e19\u003c/sup\u003e. At present, an important area of applications of isotope measurement centers on the isotope effects during photodissociation \u003csup\u003e1,2\u003c/sup\u003e. One of the best-known applications involves a mass independent isotope effect in photodissociation of SO\u003csub\u003e2\u003c/sub\u003e in the earth\u0026rsquo;s earliest atmosphere between 3.8 and 2.2 billion years ago. \u0026nbsp; Anomalous sulfur isotopic composition of ancient rock sulfides and sulfates provide a barometer of oxygen/ozone levels associated with history of photosynthesis in the Archean\u003csup\u003e20\u003c/sup\u003e. The use of stratosphere ozone formation and its associated O\u003csub\u003e2\u003c/sub\u003e anomaly are used to quantify global oceanic primary productivity and upper atmospheric photochemistry\u003csup\u003e1,2,21\u003c/sup\u003e.\u003c/p\u003e\n\u003cp\u003ePhotodissociation plays a particularly important role across space and time because its isotopic selectivity is potentially far higher than other factors. Modeling across relevant wavelengths and predicting isotope effects is intrinsically challenging, but needed as otherwise the fractionations must be measured across wide wavelengths which is not realistic in the UV region. In this paper we report a combined measurement/modelling effort to resolve all contributing parameters in photodissociation and their isotopic selectivity across a UV range. Molecular Nitrogen is chosen as all isotopic parameters are well known. Furthermore, it has a range of applications that have an immediate need and is relevant to other molecules and to contemporary space and planetary exploration and earth\u0026rsquo;s mesopheric chemistry and its linkage to space.\u003c/p\u003e\n\u003cp\u003eCosmo photochemistry does differ from other branches of chemistry in that it is typically a high energy density process, often at low material density. Challenges are both the theoretical description of elementary processes and of the simulation of gas flow \u003csup\u003e22\u003c/sup\u003e. The elementary photodissociation dynamics matter because almost always there is a maze of electronic states, see Figure 1, that are potentially relevant at the energies of interest and there is a range of coupling mechanisms of different strengths among these states \u003csup\u003e23\u003c/sup\u003e. Often these couplings are individually mass dependent, and their effective strength depends also on the spacings on the energies of the coupled states. As we discuss below the electronic state of the nascent products can therefore be dynamically non-statistical and show considerable isotopic selectivity.\u003c/p\u003e\n\u003cp\u003eNitrogen isotope measurements of extraterrestrial objects have been extensively used. This includes interstellar molecular clouds and proto stellar envelopes, and proto planetary disks, all driven by the photolysis of N\u003csub\u003e2\u003c/sub\u003e \u003csup\u003e6,25\u003c/sup\u003e. Photolysis of nitrogen in extra-terrestrial environments is a precursor of organics observed in meteorites that have uncertain synthetic pathways \u003csup\u003e8-11\u003c/sup\u003e. The photochemistry of species initiates within molecular stellar outflows and processes on gas grain chemistry, planetesimals, and their record is ultimately stored in interplanetary dust grains, meteorites, and other reservoirs, such as the lunar surface \u003csup\u003e10\u003c/sup\u003e. The complex organic species observed in carbonaceous chondrite meteorites are potentially sources of prebiotic species. Isotopic measurements with knowledge of the isotope effects provide a way to define source processes The pervasiveness of nitrogen isotopic photochemistry extends to Titan as well \u003csup\u003e26-29\u003c/sup\u003e.\u003c/p\u003e\n\u003cp\u003eAn outcome of the present work is that it might be of use in space exploration. NASAs Artemis 2 mission is set to fly its astronaut mission around the moon in 2026 and in 2028 send astronauts to land near the moons south pole and establish the first off planet inhabitation. A part of the science of importance concerns water that might be available for the future astronaut mission to Mars. Water on Mars has been a highly complex issue as there was previously water on Mars but lost over time. In the Viking Landing, the nitrogen isotopic atmosphere has a massive \u003csup\u003e15\u003c/sup\u003eN enrichment\u003csup\u003e30\u003c/sup\u003e that was first modeled by \u003csup\u003e31\u003c/sup\u003e. The enrichment was suggested as arising from selective escape of \u003csup\u003e14\u003c/sup\u003eN vs \u003csup\u003e15\u003c/sup\u003eN following N\u003csub\u003e2\u003c/sub\u003e photolysis \u003csup\u003e32\u003c/sup\u003e. A quantitative measure of the enrichment is \u0026delta;\u003csup\u003e15\u003c/sup\u003eN, the fractional excess of \u0026delta;\u003csup\u003e15\u003c/sup\u003eN over the mean isotopic composition on earth. Recently, the Curiosity Mars rover remeasured Mars nitrogen isotopic composition at \u0026delta;\u003csup\u003e15\u003c/sup\u003eN = 572 per mil, confirming Viking measurements \u003csup\u003e32\u003c/sup\u003e. As discussed, it may be due to mass-dependent escape selection, but a cometary impact could account for the enrichment as they contain high \u0026delta;\u003csup\u003e15\u003c/sup\u003eN values, between 600 and 1000 per mil \u003csup\u003e32\u003c/sup\u003e.\u003c/p\u003e\n\u003cp\u003eOf a similar vein as Mars, at 100 Km in the earth\u0026rsquo;s atmosphere the environment is such that there is no longer a Boltzmann distribution defining the interface of our atmosphere with space and atmospheric leakage to space occurs. Very little is known at the isotopic level to quantify the distillation. This is a significant component, and it is applicable to earth\u0026rsquo;s atmospheric evolution over time. There is expected isotopic chemistry as suggested for photoproduced atomic oxygen \u003csup\u003e28\u003c/sup\u003e. The only isotopic measurements of the mesosphere are from rocket borne cryogenic whole air samples where an O\u003csub\u003e2\u003c/sub\u003e anomaly is reported at 60 km \u003csup\u003e33\u003c/sup\u003e. It is expected that nitrogen will have a large fractionation due to the observed massive isotope effect and higher absorption. The new data will now allow a modeling of what to expect and guide future sampling through the mesosphere into space.\u003c/p\u003e"},{"header":"Experimental","content":"\u003cp\u003eThe experiments were all performed at the Advanced Light Source at the Lawrence Berkeley Laboratory using the UV source available at the chemical dynamics beamline. Details are described in \u003csup\u003e34-36\u003c/sup\u003e. In this work, we have maximized the experimental conditions that increase yield and lower blank allowing higher precision. A complete account in the Supplementary Information, SI, includes a schematic of the experimental set up, Figure S1, as well as the new developments specific to this work and the measured isotopic fractionation as a function of energy in Table S1.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eTheory\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe implication of our theoretical work is that the intricate dynamics of the photodissociation of N\u003csub\u003e2\u003c/sub\u003e very much matters. It implies that the outcome is not statistical and that the isotopic fractionation does reflect the initial conditions. Photo selectivity thereby provides a probe of the environment. We further argue that our considerations apply to other molecules of astrochemical interest such as CO. We discuss the essence of the modelling and why and how it applies to other systems.\u003c/p\u003e\n\u003cp\u003eA key first step is the understanding of the excited states that are accessible by a one photon transition from the electronic ground state. In N\u003csub\u003e2\u003c/sub\u003e and in most other examples, these are (quasi) bound states, states that do have enough energy but that do not directly dissociate \u003csup\u003e36\u003c/sup\u003e. Direct dissociation in N\u003csub\u003e2\u003c/sub\u003e requires an energy higher than 117,000 cm\u003csup\u003e-1\u003c/sup\u003e and is typically competing with ionization. Extensive quantum chemical studies have well characterized these singlet electronic adiabatic states in N\u003csub\u003e2\u003c/sub\u003e, e.g., \u003csup\u003e37-42\u003c/sup\u003e and identified the vibronic states e.g., \u003csup\u003e37\u003c/sup\u003e. The bound singlet vibronic states are spin-orbit very selectively coupled \u003csup\u003e43\u003c/sup\u003e to a large manifold of triplet electronic states, some of which are dissociative. Both non adiabatic and spin orbit terms couple the triplet states among themselves such that eventually but not statistically, the molecule exits on a dissociative channel. The available exit channels are identified in the potential energy curves as shown in Figure 1. Several potential energy curves for the nuclear motion are highly anharmonic. The lowest exit channel can be populated from lower lying states accessed by spin orbit coupling from the lowest singlet \u0026nbsp; state.\u003c/p\u003e\n\u003cp\u003eWe follow the quantum dynamics of the molecule from the excitation to the exit \u003csup\u003e24\u003c/sup\u003e, see SI. Our computations show that different initial conditions in each isotopomer can result in exits on a different channel, Figure 2. The isotopic selectivity is mainly due to that similar initial conditions for different isotopomers can result in different exit preferences. In N\u003csub\u003e2\u003c/sub\u003e and for other molecules such as CO, different exit channels correspond to different electronic states of the product atoms.\u003c/p\u003e\n\u003cp\u003e\u003cem\u003eThese two complementary aspects of selectivity that we demonstrate in the computations are here suggested as a dynamical origin of the exceptionally large isotopic fractionation that is seen experimentally\u003c/em\u003e, Figure 2\u003cem\u003e.\u003c/em\u003e\u003c/p\u003e\n\u003cp\u003eIn the case of N\u003csub\u003e2\u003c/sub\u003e photodissociation experiments where the N atoms are scavenged by an excess of H\u003csub\u003e2\u003c/sub\u003e, we take it that N(\u003csup\u003e2\u003c/sup\u003eD ) atoms are more than ten times more reactive towards H\u003csub\u003e2\u003c/sub\u003e than N(\u003csup\u003e2\u003c/sup\u003eP) atoms \u003csup\u003e46-51\u003c/sup\u003e and in the computations we regard N(\u003csup\u003e2\u003c/sup\u003eP) as non-reactive. In the photodissociation of CO, Carbon can exit on different electronic states. Only O(\u003csup\u003e3\u003c/sup\u003eP) atoms can exit at lower energies and O(\u003csup\u003e1\u003c/sup\u003eD) atoms are produced at an energy above 94.12nm \u003csup\u003e52\u003c/sup\u003e. For N\u003csub\u003e2\u0026nbsp;\u003c/sub\u003ethe energy threshold for producing N(\u003csup\u003e2\u003c/sup\u003eP) atoms is slightly above 89.3 nm. Thus our approach is relevant for meteorite and radio astronomy.\u003c/p\u003e\n\u003cp\u003eThe observed and the computed branching into different channels as a function of the initial state and of the isotope are shown in Figure 2 above and reported in Tables S3-S7 of the SI. It is seen to change dramatically with energy, and, in our interpretation, it is the difference in the decreasing yields of the much more reactive towards H\u003csub\u003e2\u003c/sub\u003e N(\u003csup\u003e2\u003c/sup\u003eD) atoms in the two isotopomers that is the cause of the drop in the isotopic preference at the higher energies. See also Figure S3 of the SI.\u003c/p\u003e"},{"header":"Results","content":"\u003cp\u003eOur experiment and computations, Figure 2, consistently report an exceptionally high, thousands of per mil, isotopic fractionation in the photodissociation of N\u003csub\u003e2\u003c/sub\u003e with a natural isotopic composition (0.364% \u003csup\u003e15\u003c/sup\u003eN\u003csup\u003e14\u003c/sup\u003eN). It is the higher most values reported \u003csup\u003e34\u003c/sup\u003e. The precise number depends on the excitation energy, the composition and density of the target gas, the method of detection of products, etc.. The computations reproduce and account for the observed smooth trends and provide an understanding on the contribution of the dissociation dynamics to the high isotopic fractionation. As shown in the comparison with the experimental results in Figure 2 the modelling is consistent with both the rather large magnitude and its overall shape as a function of the excitation energy. To accurately capture the observation, we bring in dynamical considerations that show a rather non monotonic variation in the electronic states of the dissociated atoms. The computed branching fractions of the different products, Figure 2(B), are in close agreement with recent molecular beam measurements for both the lighter and separately, the heavier isotopomer \u003csup\u003e44,45,53\u003c/sup\u003e. Combining the branching fractions with the absorption cross section enables us to examine, as in Figure 3, the dissociation to N(\u003csup\u003e2\u003c/sup\u003eD) and N(\u003csup\u003e2\u003c/sup\u003eP) products separately for either isotopomer. Their differences suggest a very dominant role of the dynamics in governing the isotopic fractionation at higher energies. Our computed lifetimes for dissociation \u003csup\u003e23\u003c/sup\u003e are also quite different for different initially optically excited states (S or P symmetry) and for the two different isotopomers, see SI. It is remarkable that some initial states dissociate very slowly while others, adjacent in energy, rush to exit. There can be considerable variation of the results for different physicochemical initial conditions, such as composition and column density as determined by the shielding of the incident light. Computations show decreasing selectivity at lower pressures because of reduced self-shielding, Figure S3(D). The molecular Hydrogen present in the experiment to scavenge the nascent N atoms does not significantly absorb light in the spectral range of interest and has a limited effect in the shielding computations, Figure S3(B). The central role of dynamics requires high level quantum chemistry computations of the energetics and the non-adiabatic and the state-selective spin orbit couplings, Figures S5 and S6.\u003c/p\u003e\n\u003cp\u003eBeyond astrochemistry and space physics our results of contrasting the two isotopomers are of key relevance to the long sought critical demonstration of photoselective chemistry.\u003csup\u003e54\u003c/sup\u003e We explain and illustrate by quantum dynamics that employ high level quantum chemical computations that there are two unique dynamical effects that do give rise to the spectacularly high measured isotopic enrichment. First, even small variations in the wavelength of the light can result in a different exit channel of the nascent products. This also results in considerable variations in the rate of dissociation as a function of excitation wave length. Second, at about the same wavelength, two different isotopomers can lead to products exiting on different channels. This is what laser people call a highly not statistical and state selective chemistry, a long-sought goal that using the isotopic preference we conclusively demonstrate that we achieved.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003ePerspective\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe measured photodissociation enrichment in \u003csup\u003e15\u003c/sup\u003eN with wavelength with a down trend above 90 nm is seen to arise from dynamical effects. There are two effects identified by the computations, the branching between exit channels, Figure 2 and the more subtle role of the non-monotonic variation in the individual line widths that in the higher energies begin to significantly overlap. The widths have a significant effect on both the shielding computations at the higher energies and on the cross sections themselves. The modeling requires accurate quantum dynamical simulations using state of the art multireference potential energies and their state-dependent couplings. As the excitation energy increases, competition between different coupled exit channels, some leading to reactive N (\u003csup\u003e2\u003c/sup\u003eD) and some leading to significantly less reactive N (\u003csup\u003e2\u003c/sup\u003eP) in an isotope dependent way, modulates the selectivity for the \u003csup\u003e15\u003c/sup\u003eN atoms. As a result, the dissociation lifetimes of initial states close in energy vary in a nonmonotonic isotopic dependent manner as a function of energy. Our work shows that modelling can interpret the novel experimental observations and account for the exceptionally high selectivity. Additional progress requires accurate high resolution UV spectra for entire UV bands, both measured and computed to complement fractionation measurements. The complexity of the non-statistical dynamics and the role of the light shielding make such high-resolution work necessary for the detailed understanding of isotope enrichment fractions in the higher energy regime for nitrogen and also for other molecules of interest in cosmochemistry such as CO. Given the massive range in isotopic composition, the interpretation of e.g the Mars atmosphere and photolysis intersection, meteoritic nitrogen may be modeled better. Samples from the earth\u0026rsquo;s interface with space where N\u003csub\u003e2\u003c/sub\u003e photolysis occurs would be an interesting application.\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eAcknowledgments:\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eUS–Israel NSF–BSF grant 2019722\u0026nbsp;(KK, NAG, RDL).\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eFonds National de la Recherche (F.R.S.-FNRS, Belgium), #T0205.20 (FR)\u003c/p\u003e\n\u003cp\u003eThis research used resources of the Advanced Light Source, which is a DOE Office of Science User Facility under contract no. DE-AC02-05CH11231.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eCompeting interests:\u003c/strong\u003e Authors declare that they have no competing interests.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eData and materials availability:\u003c/strong\u003e All data are available in the main text or the supplementary information.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAuthor contributions:\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eConceptualization: RDL, MHT\u003c/p\u003e\n\u003cp\u003eMethodology: KK, NAG, FR, RDL, SC, MHT\u003c/p\u003e\n\u003cp\u003eInvestigation: KK, NAG, TLJ, OK\u003c/p\u003e\n\u003cp\u003eVisualization: KK, NAG, SC\u003c/p\u003e\n\u003cp\u003eFunding acquisition: RDL, MHT\u003c/p\u003e\n\u003cp\u003eProject administration: RDL, MHT\u003c/p\u003e\n\u003cp\u003eSupervision: RDL, MHT\u003c/p\u003e\n\u003cp\u003eWriting – original draft: RDL, MHT\u003c/p\u003e\n\u003cp\u003eWriting – review \u0026amp; editing: KK, NAG, FR, OK, SC, RDL, MHT\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n \u003cli\u003eThiemens, M. 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J.\u003c/em\u003e\u003cstrong\u003e850\u003c/strong\u003e, 48 (2017). https://doi.org/10.3847/1538-4357/aa8ee7\u003c/li\u003e\n \u003cli\u003eChang, Y. C., Liu, K., Kalogerakis, K. S., Ng, C. Y. \u0026amp; Jackson, W. M. Branching Ratios of the N(D-2(3/2)0) and N(D-2(5/2)0) Spin-Orbit States Produced in the State-Selected Photodissociation of N-2 Determined Using Time-Sliced Velocity-Mapped-Imaging Photoionization Mass Spectrometry (TS-VMI-PI-MS). \u003cem\u003eJ. Phys. Chem. A\u003c/em\u003e\u003cstrong\u003e123\u003c/strong\u003e, 2289-2300 (2019). https://doi.org/10.1021/acs.jpca.8b11691\u003c/li\u003e\n \u003cli\u003eJortner, J., Levine, R. D. \u0026amp; Rice, S. A. Vol. 47 (Wiley, New York, 1981).\u003c/li\u003e\n\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[{"identity":"222e612e-e10c-491e-bf97-089764a5c35e","identifier":"10.13039/501100001742","name":"United States-Israel Binational Science Foundation","awardNumber":"112","order_by":0}],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":true,"hideJournal":true,"highlight":"","institution":"American Friends of the Hebrew University","isAcceptedByJournal":false,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true},"keywords":"Cosmochenmistry, photoselective chemistry","lastPublishedDoi":"10.21203/rs.3.rs-5896715/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-5896715/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003e\u003cstrong\u003ePhotochemical isotope effects have been measured for nearly 50 years with the driving force being the understanding of natural processes. This has ranged from climate and atmospheric chemistry and dynamics, planetary atmospheres such as Mars, Titan and Jupiter, consequences for resolving solar system formation mechanisms, interstellar molecular clouds, solar wind and meteorites. \u003c/strong\u003e\u003csup\u003e\u003cstrong\u003e1,2\u003c/strong\u003e\u003c/sup\u003e\u003cstrong\u003e The distribution of isotopomers of compounds varies significantly across the solar system and beyond, invalidating the notion of a constant molecular weight.\u003c/strong\u003e\u003csup\u003e\u003cstrong\u003e3\u003c/strong\u003e\u003c/sup\u003e\u003cstrong\u003e Nitrogen, with two stable isotopes, exhibits wide-ranging isotope ratios that arise from different sources across the solar system.\u003c/strong\u003e\u003csup\u003e\u003cstrong\u003e4-11\u003c/strong\u003e\u003c/sup\u003e\u003cstrong\u003e We seek to understand variability by explicitly examining the dynamics of photodissociation. The paper integrates measurements of photodissociation of N\u003c/strong\u003e\u003csub\u003e\u003cstrong\u003e2\u003c/strong\u003e\u003c/sub\u003e\u003cstrong\u003e at the advanced-light-source via scavenging of the nascent N atoms and state of the art dynamics modeling, including preferential light shielding.\u003c/strong\u003e\u003csup\u003e\u003cstrong\u003e12-14\u003c/strong\u003e\u003c/sup\u003e\u003cstrong\u003e We show that the exceptionally high nitrogen isotopic fractionation underscores the essential role of dynamics in interpreting photoselectivity and its dominant non-statistical aspects that we establish. High level quantum chemical computations of the relevant potentials and of their different selective couplings that vary in magnitude are vital input towards our demonstrating photoselective chemistry. Beyond N\u003c/strong\u003e\u003csub\u003e\u003cstrong\u003e2\u003c/strong\u003e\u003c/sub\u003e\u003cstrong\u003e, our approach is equally applicable for elucidating the isotope ratio reported for CO.\u003c/strong\u003e\u003csup\u003e\u003cstrong\u003e15,16\u003c/strong\u003e\u003c/sup\u003e\u003cstrong\u003e The findings support planetary exploration models, including NASA's Artemis missions, where nitrogen isotopic studies of the lunar and Martian surfaces are crucial for understanding water sources and volatile chemistry.\u003c/strong\u003e\u003c/p\u003e","manuscriptTitle":"Photoselective isotope fractionation dynamics in cosmo and atmospheric chemistry","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-01-28 07:12:47","doi":"10.21203/rs.3.rs-5896715/v1","editorialEvents":[{"type":"communityComments","content":0}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"602ec311-ac6e-47b9-b4b9-29ea48c2e8e2","owner":[],"postedDate":"January 28th, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[{"id":43381291,"name":"Physical Chemistry"}],"tags":[],"updatedAt":"2025-01-28T07:12:47+00:00","versionOfRecord":[],"versionCreatedAt":"2025-01-28 07:12:47","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-5896715","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-5896715","identity":"rs-5896715","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}