Vibrational effects in the spin-orbit autoionization of HBr

Abstract
The high resolution relative photoionization cross section for HBr is reported in the energy region between the 2Π3/2 and 2Π1/2 ionic limits. A theoretical interpretation of the spectrum is given using the multichannel quantum defect theory with an ab initio calculation of the relevant electronic quantities. The vibrational couplings due to the R variation of both the electrostatic and the spin-orbit matrix elements are introduced and are shown to be essential to reproduce the qualitative features of the experimental data in the 1052–1060 Å wavelength region.