Symmetry and Fourier analysis of the ab initio-determined torsional variation of structural and Hessian-related quantities for application to vibration–torsion–rotation interactions in CH3OH

Xu, Li‐Hong; Hougen, Jon T.; Fisher, Jonathan; Lees, R. M.

doi:10.1016/j.jms.2010.01.001

Cited by 12 publications

(2 citation statements)

References 22 publications

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“…However, the quality of the resultant Fourier series is critically dependent on good knowledge of the path taken by the internal motion. Several studies of the motions of methanol have shown that structural flexing during the internal rotation is important in reproducing the spectrum [68,69]. Attempts to implement better paths in the calculations for CH 2 DOH did not significantly improve the calculation of the K = 1 levels.…”

Section: Internal Axis Modelmentioning

confidence: 96%

The ground state torsion rotation spectrum of CH2DOH

Pearson

Drouin

2012

Journal of Molecular Spectroscopy

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Section: Internal Axis Modelmentioning

confidence: 96%

The ground state torsion rotation spectrum of CH2DOH

Pearson

Drouin

2012

Journal of Molecular Spectroscopy

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“…However, the large-amplitude torsion motion can cause the CH stretch vibrations to become effectively equivalent. In some studies of CH 3 OH, ,, the cos(τ) and cos(2τ) dependences of H cpl are likened respectively to a linear and a quadratic vibrational Jahn–Teller (or Renner–Teller) effect. Further, as recent work of Dawadi and Perry on methanol has shown, the energy differences between the CH stretch frequencies depend on the value of the COX angle (X = O in CH 3 OO and H in methanol).…”

Section: Resultsmentioning

confidence: 99%

Modeling the CH Stretch/Torsion/Rotation Couplings in Methyl Peroxy (CH₃OO)

et al. 2017

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The manifestations of CH stretch/torsion/rotation coupling in the region of the CH stretch fundamentals are explored in the CHOO radical. Following our earlier study of the fundamental in the totally symmetric CH stretch (the ν fundamental), this work focuses on the other two CH stretch fundamentals, ν and ν, which would be degenerate in the absence of a barrier in the potential along the methyl torsion coordinate. The simplest model, which assumes a decoupling of the CH stretch vibrations from the torsion, fails to reproduce several important features of the spectrum. Specifically, the absence of a strong peak around the origin of the ν fundamental and broadening of the strong peak near the origin in the observed spectrum of the ν fundamental are not captured by this model. The origins of these features are explored through two more sophisticated treatments of the torsion/CH stretch couplings. In the first, a four-dimensional potential based on the three CH stretches and the torsion is developed and shown to reproduce both of these features. On the basis of the results of these calculations, the calculated parameters are adjusted to simulate the recorded spectrum. To further explore the torsion/CH stretch couplings in CHOO, a 9-state model Hamiltonian is developed and discussed. The implications of various types of couplings on the observed energy level patterns are also discussed.

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