Spectrum of azulene. IV. Rotational analysis of the 0-0 band of the 3500 Ǻ transition

Abstract

The bands of the 3500 Ǻ transition of azulene-d_o and azulene-d_s show two unequal peaks 2.3 cm^-l apart, followed by closely spaced fine structure. These bands have been analysed as type A bands of a planar, prolate asymmetric top. Rotational constants for both molecules in the excited state have been determined. The fine structure is due to multiple line coincidences in the high-J, low-K region of the ^qP branch. To each multiple line can be attributed a running number n = J+m, where m = J-K_-1. Given sufficient resolving power, such "lines" should be rather commonly observed in type A and type B bands of large, planar, prolate molecules.