Collisional dynamics of the IF B /sup 3/Pi(0/sup +/) state. I. Pulsed excitation studies of v' = 3 and 4 at high pressure

Collisional processes in the B /sup 3/Pi(0/sup +/) state of IF were studied using temporally and spectrally resolved laser induced fluorescence. Extremely small electronic quenching rate constants (k/sub q/ .. v' = 3 rate constants for He and N/sub 2/ were (6.9 +- 0.7) x 10/sup -12/ and (3.5 +- 0.3) x 10/sup -12/ cm/sup 3/ molecule/sup -1/ s/sup -1/, respectively. For v' = 3 ..-->.. v' = 2, the respective rate constants for He and N/sub 2/ were (5.4 +- 0.5) x 10/sup -12/ and (2.5 +- 0.2) x 10/sup -12/ cm/sup 3/ molecule/sup -1/ s/sup -1/.