Quantum Chemical Modeling of Infrared (IR) and Raman Spectra for Two Symmetrical Oxazole-Based Polyene Dyes

Quantum Chemical Modeling of Infrared (IR) and Raman Spectra for Two Symmetrical Oxazole-Based Polyene Dyes The calculations were performed within the Density Functional Theory (DFT) framework using the ωB97XD functional in combination with the 6-311++G(d,p) basis set in vacuum and DMSO solvent. All calculations were carried out using the Gaussian 16 software package [1]. Initial molecular structures were constructed using the Avogadro molecular editor [2]. The calculation results are provided as Gaussian output (.log) files, including optimized geometries and vibrational frequency analyses. For one of the investigated structures, the frequency calculation revealed four imaginary frequencies in the range of approximately −90 to −113 cm⁻¹. Visualization of the corresponding normal modes showed that these motions are localized exclusively on the hydrogen atoms of the terminal methyl groups, while the conjugated polyene backbone and heterocyclic fragments remain essentially unaffected. Geometry optimization converged successfully according to all Gaussian convergence criteria. The corresponding output files are included without modification to provide complete computational records and to facilitate further analysis by interested users.