The intermolecular interaction and polar bonds aggregation induced spectral splitting phenomenon for binary mixture

In order to explain the polarization Raman noncoincidence effect of specific polar bond，and the noncoincidence phenomenon between FT-Raman and FT-IR spectra, the aggregation induced spectral splitting theory were proposed. In this paper, the vibration splitting theory was demonstrated by two strategies, improving the spectral resolution by cryogenic matrix isolation technique or finding cases where the coupling splitting is large enough to be distinguished. The band of monomer and dimer splitting were detected for acetone cryogenically isolated by Ar matrix. The polarization Raman spectra of β-propiolactone (PIL)/CCl4 binary mixture were collected at room temperature, the spectral splitting phenomenon can be clearly observed. The dynamic transformation between the monomer and dimer can be achieved and detected clearly by simply adjusting the PIL concentration. The theoretical DFT calculation based on the monomer and dimer of PIL, as well as the FT-IR and FT-Raman spectra of PIL confirmed further the observed splitting phenomenon.