PREDISSOCIATION LIFETIMES OF THE A(2)SIGMA(-DOWN SPECTROSCOPY() V=1 STATE OF THE SH RADICAL DETERMINED BY CAVITY RING)

The SH(A-X) (1,0) band has been investigated further, in absorption, u sing the technique of cavity ring-down spectroscopy, Careful lineshape measurements reveal the predissociation rate of these radicals to inc rease gradually with increasing rotational quantum number; the corresp onding lifetimes decrease from 5.5 +/- 0.2 ps (N' = 0) to 4.6 +/- 0.6 ps (N' = 8). Such behaviour has been reproduced, quantitatively, by Fe rmi's Golden Rule calculations which employ the best available (experi mentally determined) potential energy function for the A(2) Sigma(+) s tate together with ab initio curves for the dissociative 1(4) Sigma(-) State and for the R dependence of the spin-orbit matrix element linki ng these two states.