Line intensities in HBr vibration-rotation spectra

Accurate analytic expressions for electric dipole transition moments for 0-1, 0-2, and 1-2 band vibration-rotation absorption spectra are obtained following an approach developed by the authors in a previous paper. The expressions, which include anharmonic effects to the quintic potential constant, are essentially identical to those independently derived by Toth, Hunt, and Plyler. Specific calculations are made for HBr vibration-rotation intensities, comparisons being made with the observations of Babrov et al. and Rao and his colleagues. It is concluded that the data of Babrov et al. are reasonably selfconsistent, as gauged through the present theory, leading to the dipole moment function M( x) = (0.824 ± 0.02) + (0.6438 ± 0.006) x + (0.167 ± 0.06) x² Debye, x being the relative internuclear separation, {(R - R _e) }/{R _e}. The more recent higher resolution measurements of Rao and his collaborators, which lead to the dipole moment function M( x) = 0.826 + 0.482 x + 0.037 x² Debye, are far less self-consistent. It is argued that the ultimate resolution of present discrepancies cannot lie in further theoretical refinements.