Electronic to vibrational energy transfer, from Br(42P1/2) to H2O

A pulsed dye laser has been used to photolytically produce excited bromine atoms in the 4 2P1/2 state in a flowing gas mixture containing Br2, H2O, and Ar. By monitoring the time resolved molecular fluorescence from the stretching vibrations of H2O, it was possible to determine (1) the rate coefficient for the quenching of Br* by H2O, (2) the fraction of the quenching collisions which result in excitation of the (001) and/or (100) state, and (3) various V–V, R, T energy transfer rate coefficients for H2O. Our results indicate that energy transfer from Br* to H2O is a fast and mode specific process. A comparison to other Br*–hydride systems is made.