High-resolution infrared and millimeter-wave study of the v(3)=1 state of HSiF3 and DSiF3

Millimeter-wave spectra of HSiF3 and DSiF3 in the v(3) = 1 excited state ha ve been measured from 100 to 490 GHz. Infrared spectra have been recorded i n the v(3) regions, v(0) 424.0301 and 420.9320 cm(-1) in HSiF3 and DSiF3, r espectively, with a resolution of 2.4 X 10(-3) cm(-1). Since in both specie s the parameters alpha(3)(B) and alpha(3)(C) have very similar values, no K structure could be resolved in the P-Q and R-Q clusters for low-to-medium K values. For high J the effect of the ground state D-JK term more and more dominates and spreads the J clusters into opposite directions such that me dium-to-high K components, particularly those with K = 3p, are resolved. Ro tational and infrared data have been fitted together using a model up to se xtic centrifugal distortion constants. No perturbations were indicated. Hot bands (v(3) + nv(6))-nv(6) with n = 1, 2, and 3 have been detected and ana lyzed. (C) 2000 Academic Press.