Vibration-Rotation Bands of Phosphine-d1: Analysis of the ν3a and ν2 Bands

The ν3a (PD stetching mode) and ν2 (inversion mode) bands of the PH2D molecule have been analyzed. The ν3a band is of type A while the ν2 band is an A/C-hybrid band. It was found that the observed ground state combination differences could not be reproduced with the parameters reported in the literature (McRae et al., J. Mol. Spectrosc.116, 58-70(1986)). Improved ground state parameters have been obtained by a simultaneous least-squares fit of the microwave data and the ground state combination differences from the ν3a, and ν2 bands. The parameters of the ν3a, and ν2 states up to the sextic distortion terms have been determined by a least-squares fit of 505 and 842 lines with RMS deviations of 4.0 × 10−4 and 4.9 × l0−4 cm−1, respectively.