The nu(2) Bands of the Deuterated Species D(2)Se and HDSe

For the first time D(2)Se and HDSe as (80)Se monoisotopic and natural material were studied in the region of the nu(2) fundamental vibration by high-resolution (0.0033 cm(-1)) Fourier transform infrared spectroscopy. For D(2)Se which is an asymmetric rotor with C(2v) symmetry the nu(2) band is of B type while for HDSe (C(s) symmetry) it is a hybrid band, and both A- and B-type transitions were observed. Depending on the isotopic abundances, 300-1000 lines were assigned for each of the isotopic (M)Se species (M = 76, 77, 78, 80, and 82). The corresponding (010) experimental rotational levels, obtained by adding the observed line positions to the ground state levels derived from J.-M. Flaud, Ph. Arcas, O. N. Ulenikov, G. A. Onopenko, N. E. Tyabaeva, W. Jerzembeck, and H. Bürger, (J. Mol. Spectrosc., in press) were fitted satisfactorily using a Watson-type Hamiltonian in A reduction and I(r)-representation: the rms deviations are ranging from 1.5 to 4.3 x 10(-4) cm(-1) depending on the isotopic species. Hamiltonian constants up to high order (octic terms) were determined for each isotopic species. For the most abundant Se isotopic species, namely (80)Se, the band centers are nu(0) (D(2)(80)Se) = 741.67503 cm(-1) and nu(0) (HD(80)Se) = 900.43820 cm(-1). Copyright 1999 Academic Press.