ELECTRONIC QUENCHING RATE CONSTANTS OF KRF(B,C) AND KR2F-ASTERISK

The laser-assisted reaction between Kr and F2 was used to generate KrF (B,C) molecules during a 7 ns laser pulse in a stainless steel cell. T he first-order decay rates of the collisionally coupled KrF(B) and KrF (C) states in greater-than-or-equal-to 50 Torr of Kr buffer gas were m onitored by the KrF(B-X) fluorescence in the presence of added reagent s at 300 K. Two-body quenching rate constants for KrF(B,C) by diatomic and polyatomic molecules and the rare gases were determined from the pressure dependence of the first-order decay constants of KrF(B,C). Th e mixed three-body quenching rate constants (with Kr) for added He, Ne , and Ar were also measured. For Kr pressure above 200 Torr, Kr2F(4 2G AMMA) molecules were formed via three-body quenching of KrF(B,C), and the quenching rate constants for Kr2F(4 2GAMMA) by the same set of rea gents were determined. The general trends in the quenching constants f or KrF(B,C) and Kr2F(4 2GAMMA) are similar to those for XeCl(B,C) and Xe2Cl(4 2GAMMA), respectively; however, the rate constants for KrF(B,C ) and Kr2F(4 2GAMMA) are generally larger than for the corresponding x enon chloride molecules. Quenching mechanisms for KrF(B,C) and Kr2F(4 2GAMMA) are discussed.