FTIR STUDY OF THE NU-7 BAND OF PH3F2 NEAR 340 CM-1

The ν7±1 (e′) band of PH3F2 near 340 cm-1 has been studied by FTIR spectroscopy with a resolution of 3 × 10-3 cm-1. One thousand six hundred twenty observed transitions have been fitted, σ = 2.5 × 10-4 cm-1, to 17 excited state parameters including q7(+) and q7(+)J. Q branches of the hot bands 2ν70-ν7±1 and 2ν7±2-ν7±1 were identified and anharmonic constants x77 and g77 determined. Combination of data on ν7±2, 2ν7±2-ν7±1 with those on 2ν7±2 available from a previous study yielded an improved value of the axial rotational constant, A0 = 2.868(3) cm-1. The results are compared with predictions obtained recently by ab initio calculations. © 1992.