Highly resolved structure of the electronic spectra of azulene in frozen hydrocarbon matrices

• Published in: Journal of molecular structure 1975-01, Vol.28 (1), p.5-24
• Main Authors: Olszowski, A., Ruziewicz, Z., Chojnacki, H.
• Format: Article
• Language: English
• ISSN: 0022-2860; 1872-8014
• DOI: 10.1016/0022-2860(75)80039-1

Vibronic structures of electronic spectra of azulene embedded into various hydrocarbon matrices are examined at 77°K. High-resolution spectra are obtained using crystalline matrices of isooctane and methylcyclohexane. The O-O bands of third and fourth electronic transitions (33836 and 35550 cm −1, respectively, in the low-temperature modification of the isooctane matrix) are identified in the absorption spectrum of azulene. Using the P-P-P approximation with the unified parametrization the lowest excited states energies as well as bond lengths for the S o and their respective changes in the S 1 and S 2 electronic states are calculated. Differences in the vibrational frequencies found for the respective electronic states of the azulene molecule are discussed in connection with the lack of the mirror symmetry between the S 2← S o absorption and S 2→ S o fluorescence.