Isotope Substitution in Near Local Mode H2X Molecules: The ν1 and ν3 Bands of D2Se

Abstract

The high-resolution (0.0027 cm−1) Fourier transform spectra of the D2Se molecule as 80Se monoisotopic and natural material were recorded for the first time in the 1500–1900 cm−1 region where the ν1 and ν3 vibration–rotation bands are located. Because accurate information about the rotational structures of different vibrational states was still lacking, the isotopic relations between rotational, centrifugal distortion, resonance interaction, etc., parameters of the H2Se and D2Se species were derived and successfully used for the construction of a synthetic spectrum for the ν1 and ν3 bands. As a result, lines of the recorded spectrum were assigned, and band centers, rotational, centrifugal distortion, and resonance interaction parameters for the (100) and (001) states of the species D2MSe, M = 76, 77, 78, 80, and 82, were determined. The obtained sets of parameters reproduce values of the vibration–rotation energies with a “mean” accuracy of 0.00007 cm−1 for the D280Se, and a slightly worse accuracy for other Se isotopic species.