High-Resolution Infrared Spectra and Simultaneous Rovibrational Analysis of the ν2, ν3, ν5, and ν6Bands of H3SiF

✍ Scribed by D. Papoušek; H. Bürger; A. Rahner; P. Schulz; H. Hollenstein; M. Quack

• Publisher: Elsevier Science
• Year: 1999
• Tongue: English
• Weight: 615 KB
• Volume: 195
• Category: Article
• ISSN: 0022-2852
• DOI: 10.1006/jmsp.1999.7819

✦ Synopsis

A high-resolution FT infrared spectrum of H 3 SiF (resolution 0.0024 cm Ϫ1 ) in the region 620 -1130 cm Ϫ1 was measured and used to analyze the fundamental bands 2 ( A 1 ), 990.851 cm Ϫ1 ; 3 ( A 1 ), 875.011 cm Ϫ1 ; 5 (E), 962.213 cm Ϫ1 ; and 6 (E), 729.528 cm Ϫ1 . A total number of 7241 transition wavenumbers (including 53 perturbation-allowed transitions) with JЈ Յ 49 have been fitted by taking into account various Coriolis interactions, ␣-resonance terms, and ᐉ-type interactions between and within the vibrational levels v 2 ϭ 1, v 3 ϭ 1, v 5 ϭ 1, and v 6 ϭ 1. The strongest interaction in this system of levels is the x-y Coriolis coupling between the v 2 ϭ 1 and v 5 ϭ 1 vibrational states. However, it turns out that the x-y and z-type Coriolis interactions also have to be introduced explicitly between the v 5 ϭ 1 and v 6 ϭ 1 states as well as the x-y Coriolis interactions between v 3 ϭ 1 and v 5 ϭ 1, and v 3 ϭ 1 and v 6 ϭ 1 states, in order to fit the data quantitatively. The standard deviation of the fit was ϭ 8.6 ϫ 10 Ϫ5 cm Ϫ1 for 7241 transition wavenumbers and 68 fitted parameters. The sign relations between the fitted parameters and the possibility of fitting the parameters in different schemes are discussed. The results have been used to find close coincidences between the frequencies of the CO 2 laser lines and the transition wavenumbers of the 2 and 5 bands of H 3 SiF for the main natural isotopomer. We report integrated absorption band strengths which are important for infrared laser chemistry.