Vibration–rotation interactions in H2, HD and D2 : centrifugal distortion factors and the derivatives of polarisability invariants. (3rd March 2020)

• Record Type: Journal Article
• Authors: Raj, Ankit; Witek, Henryk A.; Hamaguchi, Hiro-o
• Is Part Of: Molecular physics. Volume 118:Number 5(2020)
• Publication Date: 2020-03-03
• Subjects: Polarisability -- hydrogen molecule -- polarisability invariants -- Raman spectroscopy; Molecules -- Periodicals; Chemistry, Physical and theoretical -- Periodicals; Molécules -- Périodiques; Chimie physique et théorique -- Périodiques; 539.6.05
• DOI: 10.1080/00268976.2019.1632950
• Languages: English
• ISSNs: 0026-8976

Abstract

ABSTRACT: We report the correction factors for centrifugal distortion in Raman intensities for pure rotation (O0- and S0-branch) and vibration–rotation (O1- and S1-branch) transitions in the ground electronic state of H2, HD and D 2 . These factors are presented for 52 selected excitation wavelengths and for the initial rotational states, J = 2 − 21 . This data is useful in applications of intensity calibration of spectrometers and the spectroscopy of flames. The classical treatment of centrifugal distortion involved the expansion of polarisability anisotropy ( γ ) over the internuclear distance, while assuming the diatomic molecule behaves as a harmonic oscillator. Here, this approximation of polarisability invariants as a Taylor series expansion is tested, revealing that truncation up to the second-order derivatives of mean polarisability ( α ¯ ) and polarisability anisotropy ( γ ) gives faithful representations, yielding accurate expectation values with error < 0.2 %, for the ground rovibrational state and for the fundamental transition. GRAPHICAL ABSTRACT: UF0001