CO 2 laser Stark spectroscopy of the Coriolis-coupled ν2 and ν5 bands of CD 3Br

Abstract

The ν 2 (CD 3 symmetrical deformation) and ν 5 (CD 3 degenerate deformation) fundamental bands of CD 3Br were studied by 9.4- and 10.4-μm CO 2 laser Stark spectroscopy. Stark resonances originating from 28 and 53 rovibrational transitions of the ν 2 and ν 5 bands, respectively, were assigned for each of the isotopic species, CD 3 79Br and CD 3 81Br. These two bands were simultaneously analyzed with explicit inclusion of the ν 2- ν 5 Coriolis interaction, yielding precise molecular constants in the ν 2 and ν 5 excited states as well as the Coriolis coupling constant. The molecular constants obtained are consistent between the two isotopic species and are in good agreement with the results of high-resolution infrared studies. The band origins and dipole moments are CD 3 79Br CD 3 81Br ν 2 991.396 82 (18) 991.388 46 (17) cm −1 ν 5 1055.469 00 (12) 1055.466 32 (12) cm −1 μ 0 1.830 42 (52) 1.829 84 (47) D μ 2 1.829 93 (48) 1.829 57 (46) D μ 5 1.832 23 (60) 1.831 19 (56) D where the figures in parentheses are three times the standard deviations in the least-squares fit.