The rotation–vibration spectrum of methyl fluoride from first principles

Owens, Alec; Küpper, Jochen; Thiel, Walter; Yachmenev, Andrey; Yurchenko, Sergei N.

doi:10.1039/C8CP01721B

Journal Article

PUBDB-2018-02644

The rotation–vibration spectrum of methyl fluoride from first principles

Owens, A. (Corresponding author)CFEL* ; Yachmenev, A.CFEL*DESY* ; Küpper, J.CFEL*DESY* ; Yurchenko, S. N. ; Thiel, W.

2018
RSC Publ. Cambridge

Physical chemistry, chemical physics 21, 3496 - 3505 (2018) [10.1039/C8CP01721B]

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Please use a persistent id in citations: doi:10.1039/C8CP01721B doi:10.3204/PUBDB-2018-02644

Abstract: Accurate ab initio calculations on the rotation–vibration spectrum of methyl fluoride (CH$_3$F) are reported. A new nine-dimensional potential energy surface (PES) and dipole moment surface (DMS) have been generated using high-level electronic structure methods. Notably, the PES was constructed from explicitly correlated coupled cluster calculations with extrapolation to the complete basis set limit and considered additional energy corrections to account for core-valence electron correlation, higher-order coupled cluster terms beyond perturbative triples, scalar relativistic effects, and the diagonal Born–Oppenheimer correction. The PES and DMS are evaluated through robust variational nuclear motion computations of pure rotational and vibrational energy levels, the equilibrium geometry of CH$_3$F, vibrational transition moments, absolute line intensities of the $\nu_6$ band, and the rotation–vibration spectrum up to $J=40$. The computed results show excellent agreement with a range of experimental sources, in particular the six fundamentals are reproduced with a root-mean-square error of 0.69 cm$^{-1}$. This work represents the most accurate theoretical treatment of the rovibrational spectrum of CH$_3$F to date.

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