Collisional dynamics of the BrF B 3Π(0+) state. I. Electronic quenching

Abstract

Pulsed laser induced fluorescence techniques have been used to study electronic quenching of the B 3Π(0+) state of bromine monofluoride. BrF(B) deactivation rate coefficients were determined at room temperature for vibrational levels v′=2, 5, and 6 and for the following collision partners: Ar, SF6, CF4, N2, O2, CO2, and Br2. The quenching rate coefficients ranged from <6×10−14 cm3/molecule s for Ar to 6.9×10−11 cm3/molecule s for Br2. The radiative lifetime for v′=5 was determined as τr=59.6±0.4 μs. Double exponential decays were observed with molecular oxygen, indicating two distinct mechanisms for collisional deactivation. The BrF(B–X) total fluorescence increases at early times when the collision partner SF6 is added. This result is attributed to efficient vibrational relaxation to the states v′=1 and 0 which are detected most efficiently.