THE OBRO C((2)A(2))[-X(B-2(1)) ABSORPTION-SPECTRUM

The highly structured visible absorption spectrum of the bromine dioxi de radical, OBrO, has been observed in the 15 500-26 000 cm(-1) region . The spectrum is dominated by a long progression in the Br-O symmetri c stretching motion (nu(1)') and a series of short progressions built on the bending mode (nu(2)'); there are no features associated with th e excitation of the antisymmetric stretching mode (nu(3)'), The spectr um also contains numerous transitions originating from the (0,1,0) and (1,0,0) vibrational levels of the electronic ground state, X(B-2(1)), A simultaneous fit to all of the observed vibronic features yielded t he frequencies nu(1) ''=799.4 cm(-1), nu(2) ''=317.5 cm(-1), omega w(1 )=641.5 cm(-1) omega(2)' = 210.7 cm(-1), and a band origin T-0 = 15 86 3 cm(-1). Franck-Condon simulations combined with ab initio calculatio ns of the four lowest OBrO doubler electronic states identify the spec trum as arising from the C((2)A(2))<--X(B-2(1)) electronic transition. (C) 1997 American Institute of Physics.