RADIATIVE LIFETIMES OF NiH AND CoH

$^{a}$ S. A. Kadavthu, R. Scullman, R. W. Field, J. A. Gray, and M. Li, J. Mol. Spectrosc, 147, 448-470 (1991). $^{b}$ T.D. Varberg, E. J. Hill, and R. W. Field, J. Mol. Spectrosc, 138, 630-637 (1989).Author Institution: Department of Chemistry, Ohio Northern UniversityRadiative lifetimes have been measured for several excited electronic states of NiH and radicals, which are produced by laser ablation in a pulsed free-jet expansion of argon containing pentane vapor. $Known^{ab}$ transitions in the 15,500 to $18,200 cm^{-1}$ region were excited using a pulsed dye laser, and lifetimes varying from approx. 0.5 to $5 \mu s$ were determined by temporally resolving the fluorescence intensity. The lifetimes of some states depend on rotational level and/or parity, The electronic structure of transition-metal radicals is generally difficult to model or theoretically predict, especially for optically excited states. While observations such as magnetic moments, A-doubling, and spin-orbit intervals can aid in understanding perturbations, radiative lifetimes may be a better diagnostic for assigning the spin multiplicity of the excited states when the low-lying states have will-defined spin