High resolution study of the 6ν1 P-H stretching band of the PHD2 molecule

The high resolution spectrum of a phosphine gas mixture containing PHD₂ was recorded at room temperature in the 12 550-12 770 cm⁻¹ region. A high sensitivity laser photoacoustic spectrometer consisting of a longitudinal resonant cell coupled to a Ti:sapphire ring laser was employed. More than 600 transitions were assigned to the 6ν₁ overtone band of PHD₂ up to J^max=20, K_a^max=6. A Hamiltonian model developed up to the octic centrifugal distortion terms was used. Seven rotational and centrifugal distortion parameters were fitted, the other ones being fixed to their values linearly extrapolated from ν₁ and 2ν₁. The derived parameters reproduce the initial data within the experimental uncertainties. The isolated character of the P-H bond is confirmed.