Rovibronic bands of the à B22←X̃ B21 transition of C6H5O and C6D5O detected with cavity ringdown absorption near 1.2 μm

Chi-Wen Cheng, Henryk Witek, Yuan-Pern Lee
2008 Journal of Chemical Physics  
We recorded several rovibronic bands of C 6 H 5 O and C 6 D 5 O in their à 2 B 2 ← X 2 B 1 transitions in the range 1.14-1.31 m with the cavity ringdown technique. While the electronic transition is forbidden, several vibronic bands are observed. By comparison of rovibronic contours of observed and simulated bands to determine their types of transition, and by consideration of vibrational wavenumbers of the upper state based on quantum-chemical calculations, we were able to provide vibronic
more » ... rovide vibronic assignments of observed bands and derive several experimental vibrational wavenumbers ͑given as in unit of cm −1 in this paper͒ for the à 2 B 2 state, namely, 12 = 947, 13 = 793, 14 = 417, 15 = 964, 16 = 866, 17 = 723, 18 = 680, and 19 = 499 for C 6 H 5 O, and 12 = 772, 13 = 626, 14 = 365, 15 = 812, 17 = 599, 18 = 532, and 19 = 436 for C 6 D 5 O. Transitions involving vibrationally excited levels of 20 were also observed; 20 of the à state is greater by 50 cm −1 than the X state of C 6 H 5 O. A weak origin at 7681 cm −1 for the à ← X transition of C 6 H 5 O ͑7661 cm −1 for C 6 D 5 O͒ with a c-type contour was observed. Observed isotopic ratios of vibrational wavenumbers for the à state of C 6 H 5 O to those of C 6 D 5 O are in good agreement with the predictions from quantum-chemical calculations at the B3LYP/aug-cc-pVTZ level.
doi:10.1063/1.2992077 pmid:19045193 fatcat:dtdpetmdmnazxep6ybf4njxxhy