Vibrational spectra and force constants of symmetric tops: XXV. Rovibrational spectrum of the fundamental v 6 of H3SiI near 600 cm-1

The infrared spectrum of H 3 SiI has been investigated with a resolution of 0·04 cm -1 in the region of the fundamental v 6 near 600 cm -1 . About 2000 ΔK, ΔJ = ±1 lines have been measured, assigned and fitted by different models, and a σ(J, K) value of 3·9 × 10 -3 cm -1 has been achieved in the least-squares procedure. The hot bands 2v 6 ±2 - v 6 ±1 and 2v 6 0 - v 6 ±1 have been detected and confirmed by a rovibrational analysis of the parallel and perpendicular components of 2v 6 . Information concerning the perturbed v 3 + v 6 state has been obtained from the analysis of v 6 + v 3 - v 3 for which several Q branches were detected and assigned.