High-resolution infrared and ab initio investigation of CHD279Br: Ro-vibrational analysis of the ν6 fundamental and the 2ν6−ν6 hot band

• Published in: Molecular physics Vol. 118; no. 18
• Main Authors: Stoppa, P, De Vito, D, Giorgianni, S, Baldacci, A, Gambi, A, Larsen, R Wugt
• Format: Journal Article
• Language: English
• Published: Abingdon Taylor & Francis Ltd 15.09.2020
• Subjects: Fourier transforms; High resolution; Infrared analysis; Mathematical analysis; Parameters; Spectroscopy; Spectrum analysis; Vibrational states
• ISSN: 0026-8976; 1362-3028
• DOI: 10.1080/00268976.2020.1766141

The high-resolution infrared spectrum of CHD279Br has been investigated by Fourier transform spectroscopy in the range 540–615 cm−1 at an unapodised resolution of 0.0035 cm−1. This spectral region is characterised by the ν6 fundamental (584.8510 cm−1), corresponding to C–Br stretching mode, and its hot band 2ν6−ν6 (578.4333 cm−1). The spectral analysis resulted in the identification of 3430 transitions (J’ ≤ 73 and K'a ≤ 18) for the ν6 fundamental and 1212 transitions (J’ ≤ 49 and K'a ≤ 11) for the hot band 2ν6−ν6. The assigned data have been fitted using the Watson’s S-reduced Hamiltonian in the Ir representation and new constants for the ground state from about 24,600 combination differences and sets of parameters for the v6 = 1 and 2 vibrational states have been obtained. From spectral simulations the intensity ratio between 2ν6−ν6 and ν6 has been estimated to be 0.15 ± 0.02. High-quality ab initio calculations have also been performed at the CCSD(T) level of theory in order to support the experimental investigation through the calculation of molecular parameters relevant to ro-vibrational spectroscopy.