ANALYSIS OF B-TYPE VIBRATION-ROTATION BAND OF METHANE D2 IN REGION 5880-6136 CM-1

A type B band of the asymmetric rotor molecule methane d2 was observed in the 5880-6136 cm-1 region. The band was assigned as 2ν3b, the first overtone of the ν3b band observed by Wilmshurst and Bernstein. The analysis of the band utilized the Kivelson and Wilson approximation for centrifugal distortion corrections to the energy levels. Assignments were made for transitions having values of J = 0 to J = 12. A tracing of the observed spectrum of the band has been given along with the predicted spectrum of the band. Values were obtained for the rotational constants: A-or+ = 4·301, B-or+ = 3·505, C-or+ = 3·054 cm-1 for the ground vibrational state and Aprime = 4·247, Bprime = 3·462, Cprime = 3·025 cm-1 for the upper vibrational state. The band centre was located at 5999·126 cm -1. Centrifugal distortion constants were calculated for the ground vibrational state and estimates were made of the upper-state centrifugal distortion constants.