The Effect of Nuclear Quadrupole Hyperfine Interaction on the Infrared Absorption Band ν6 of 12CH3I

• Published in: Journal of molecular spectroscopy Vol. 157; no. 1; pp. 122 - 131
• Main Authors: Paso, R., Alanko, S.
• Format: Journal Article
• Language: English
• Published: San Diego, CA Elsevier Inc 01.01.1993; Elsevier
• Subjects: Atomic and molecular physics; Exact sciences and technology; Fine and hyperfine structure; Molecular properties and interactions with photons; Physics; Properties of molecules and molecular ions; Rotational constant; Theoretical study; Centrifugal distortion constant; Experimental study; Quadrupolar interaction; Absorption spectrum; Hyperfine structure; Rovibrational transition; Molecular constant; Iodomethane; Infrared spectrum; Iodocarbon; Organic compounds
• ISSN: 0022-2852; 1096-083X
• DOI: 10.1006/jmsp.1993.1010

A high-resolution absorption spectrum of the perpendicular fundamental ν6 of 12CH3I was recorded. The band was analyzed essentially as an unperturbed perpendicular band, although a small Coriolis interaction with 2ν3 was taken into account. A least-squares fit with 19 molecular parameters was performed. The splittings and shifts in line positions caused by the nuclear quadrupole hyperfine effect were investigated, and the influence of this effect on the results of the least-squares fit was studied. The correction of the hyperfine effect increases the amount of acceptable lines by more than 10% in the least-squares fit. The influence of these additional observations on the molecular constants is generally within the statistical error limits, but for some higher order parameters the changes are more considerable.