QUANTUM RESOLVED ROTATIONAL ENERGY-TRANSFER IN THE B (3)PI(0(U)(-2())STATE OF BR)

Steady-state spectrally resolved laser-induced fluorescence techniques have been used to study rotational energy transfer within the B 3PI(0 u+) state of molecular bromine. Rate coefficients for electronic quenc hing and state-to-state rotational energy transfer within vibrational state v'=11 were determined for Br2, He, Ar, and Xe collision partners . The individual, state selective rotational transfer rate coefficient s were an order of magnitude slower than electronic quenching rates. E lectronic quenching is attributed to both collisional predissociation and energy transfer followed by rapid spontaneous predissociation. For Br2 (B, v'=11, J'=35) collisions with helium, population in the state s J'=19-47 were observed and the resulting state-to-state rotational t ransfer rate coefficients ranged from 6.2 X 10(-11) to 6.5 X 10(-12) c m3/molecule s. Both exponential energy gap and statistical power gap l aws for the scaling of rotational energy transfer rate coefficients wi th rotational energy are compared to the observed data.