Electronic transition moment and rotational transition probabilities in CH .1. A (2)Delta-X(2)Pi system

Vibrational band transition probabilities of the A-X electronic system of CH, nu'=0, 1, and 2, have been measured in a low pressure flame using laser-induced fluorescence. These results improve earlier experiments that were complicated by energy transfer contributions, and expand measurements to very weak off-diagonal bands such as 0,2 and 1,3. The electronic transition moment derived from the vibrational branching ratio measurements differs slightly from ab initio calculations. Honl-London factors using a mixed coupling scheme have been tested by experiment. Finally, a combination of these results with previously measured radiative lifetimes yields absolute absorption and emission coefficients for this system. A comparison between computed radiative lifetimes and collision-free experimental lifetimes suggests a predissociation rate in nu'=0, N'>17 of similar to 1.5X10(5) s(-1). (C) 1996 American Institute of Physics.