CO2 laser Stark spectroscopy of the ν4 band of SiDF3: The C0 rotational constant and vibrationally induced dipole moment

Rovibrational Spectroscopy of the v5 = 1 Level of 28SiDF3

“…[1] with the l-dependent terms removed and supplemented with the matrix element of the ⌬k ϭ Ϯ6 interaction [5] to retain consistency with the recent studies of other fundamental bands (6,7). The ⌬k ϭ Ϯ6 interaction was, however, neglected in the upper level because we have not refined the parameters of the sixth-order terms of the effective Hamiltonian which were beyond significance for the reproduction of our current data.…”

“…This separation together with a small C-B value excludes the possibility of resonant level crossings with the v 5 ϭ 1 level due to Coriolis interaction. However, the kl Ͼ 0 levels of v 5 ϭ 1 approach the levels of v 6 ϭ 2, which interact through the ␣ resonance (⌬k ϭ Ϯ2, ⌬l ϭ ϯ1) with a resonance estimated to occur for kl 5 Ϸ 20.…”

“…Finally, they also determined an equilibrium structure. Harada et al measured the laser Stark spectra of the 4 band in both SiHF 3 (4) and SiDF 3 (5) and determined the C 0 rotational constant from perturbation-allowed transitions generated by the l (2,Ϫ1) resonance. This v 4 ϭ 1 state (6) and the v 6 ϭ 1 (7) were recently reanalyzed with the assignment based on newly measured and much better resolved rotational and rovibrational spectra.…”

“…In this paper, we present an analysis of the rotationally resolved FTIR spectrum of the last of the degenerate fundamental bands, 5 (SiD rocking vibration), and the corresponding MW and SMMW transitions in the v 5 ϭ 1 level.…”

“…We had to exclude from fitting transitions pertaining to the kl ϭ ϩ17, ϩ18, and ϩ21 levels (i.e., about 200 transition wavenumbers) as they had residuals exceeding 0.04 cm Ϫ1 . This can be explained qualitatively by the ␣ resonance (⌬k ϭ Ϯ2, ⌬l ϭ ϯ1) between the l 5 ϭ ϩ1 and l 6 ϭ ϩ2 levels for kl 5 Ϸ 20, which follows from the estimation of constants of the v 6 ϭ 2 ϩ2 levels based on the recent study of the 6 band (7) and force field of SiDF 3 (8).…”