The ground vibrational states of PH2D and PHD2

The high resolution (2.3-3.1 x 10(-3) cm(-1)) Far infrared Fourier transform spectrum of PH2D and PHD2 was recorded in the 20-160 cm(-1) region. Assignments were made using a specially developed computer-assisted automatic 'two pair transition' method. Altogether, 1300 and 590 infrared transitions of the PHD2 and PH2D species, respectively, were fitted together with appropriately weighted microwave transitions to derive the rotational and centrifugal distortion parameters up to eighth order of the ground vibrational states of both molecules. The parameters obtained from these fits reproduce the microwave transitions with accuracies close to experimental uncertainties. A few of microwave transitions were shown to be blended, or misassigned. The rms deviations for the infrared data are 1.01 x 10(-4) and 1.05 x 10(-4) cm(-1) for PH2D and PHD2, respectively, which is also close to the experimental uncertainty. (C) 2001 Elsevier Science B.V. All rights reserved.