SPECTROSCOPY OF BABR - ROTATIONAL ANALYSIS OF THE A(2)PI-X(2)SIGMA-X(2)SIGMA+ TRANSITIONS OF THE BA-138 BR-81 ISOTOPOMER( AND B(2)SIGMA+)

The first rotational analysis of BaBr has been performed. The near-inf rared A2PI-X2SIGMA+ and B2SIGMA+-X2SIGMA+ band systems of BaBr were re corded in absorption by using Fourier transform spectroscopy (FTS). La ser induced fluorescence spectra from both systems obtained by excitin g with a Ti: sapphire single mode laser were recorded with FTS techniq ues in order to simplify the otherwise dense spectra. No direct combin ation difference approach was possible in order to analyse the absorpt ion bands in detail, why the rotational line measurements were process ed using semiautomatic iterative routines for synthesizing and evaluat ing molecular spectra. Resolved rotational data consisting of around 5 000 lines of Ba-138Br-81, originating from 10 vibrational bands includ ing the vibrational levels nu = 0-2 of the A2PI and X2SIGMA+ states an d nu = 0-1 of the B2SIGMA+ state, were used in the final analysis. The observed anomalous intensity distribution and the interaction between the A2PI and B2SIGMA+ states are discussed.