High-Resolution FTIR Study of the PH Stretching Bands ν1 and ν5 of PH2F and PH2Cl

The FTIR spectra in the ν1 and ν5 (PH stretching) regions of the short-lived molecules PH2F and PH2Cl have been recorded with a resolution of 5.5 × 10−3 cm−1. The rovibrational analysis of the A/C- and B-type bands yielded excited state parameters, and relative transition moments of the ν1 and ν5 bands as well as the μA:μC ratio of ν1 were estimated by band contour simulations. The band centers were determined: PH2F, ν1 2283.11950(4), ν5 2286.97185(4); and PH235CI, ν1 2203.43762(4), ν5 2309.67696(4) cm−1. In PH2F, weak c-type Coriolis resonance effects with ζc1,5 = 0.0120 were found to affect the Ka = 1 and Ka = 0 levels of ν1 and ν5, respectively. The experimental results are in good agreement with previously reported predictions from ab initio harmonic and anharmonic force fields.