HIGH-RESOLUTION STUDY OF THE INFRARED-SPECTRUM OF H3SII IN THE REGIONS 330-680 AND 1070-1360 CM(-1) - ACCURATE DETERMINATION OF THE GROUND-STATE CONSTANTS

High-resolution FTIR spectra of H3SiI have been recorded in the region s 330-680 cm(-1) (nu(3)/nu(6)) and 1070-1360 cm(-1) (2 nu(6)). A detai led rovibrational study was carried out for the nu(3) and nu(6) fundam ental bands, 2 nu(6)(+/-2) and 2 nu(6)(0) overtone bands, and two hot bands, 2 nu(6)(+/-2) - nu(6)(+/-1) and 2 nu(6)(0) - nu(6). A local res onance between the nu(6) = 2 and nu(2) = nu(3) = 1 states was observed . Ground state combination differences deduced from the nu(3), nu(6), 2 nu(6)(+/-2), and 2 nu(6)(0) bands allowed us to obtain accurate B-0, D-J(0), and D-JK(0) constants. The nu(6), 2 nu(6)(+/-2) - nu(6)(+/-1) and 2 nu(6)(+/-2) bands were used for the experimental determination of the A(0) and D-K(0) constants, whereas the hot band 2 nu(6)(0) - nu (6) served to make the internal calibration coherent. Ground state dif ferences Delta(K)(J) = E-0(J,K) - E-0(J,K - 3) were calculated with K up to 12. By a least-squares fit, we obtained the following results: A (0) = 2.8426037(14) cm(-1) and D-K(0) = 2.75840(99) x 10(-5) cm(-1). ( C) 1997 Academic Press.