Effects of External Field Wavelength and Solvation on the Photophysical Property and Optical Nonlinearity of 1,3-Thiazolium-5-Thiolates Mesoionic Compound

The photophysical property and optical nonlinearity of an electronic push-pull mesoionic compond, 2-(4-trifluoromethophenyl)-3-methyl-4-(4-methoxyphenyl)-1,3-thiazole-5-thiolate were theoretically investigated with a reliable computing strategy. The essence of the optical properties were then explored through a variety of wave function analysis methods, such as the natural transition orbital analysis, hole-electron analysis, (hyper)polarizability density analysis, decomposition of the (hyper)polarizability contribution by numerical integration, and (hyper)polarizability tensor analysis, at the level of electronic structures. The influence of the electric field and solvation on the electron absorption spectra and (hyper)polarizabilities of the molecule are highlighted and clarified. This work will help people to understand the influence of external field wavelength and solvent on the optical properties of mesoionic-based molecules, and provide a theoretical reference for the rational design of chromophores with adjustable properties in the future.