A global ab initio dipole moment surface for methyl chloride

Owens, Alec; Yurchenko, Sergei N.; Yachmenev, Andrey; Tennyson, Jonathan; Thiel, Walter

doi:10.1016/j.jqsrt.2016.06.037

Cited by 15 publications

(17 citation statements)

References 78 publications

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“…These systems have been treated within the ExoMol framework19 and we refer the reader to the relevant publications for details of the ro-vibrational calculations51525354. Candidate ro-vibrational states were identified by sorting the files according to upper state energy.…”

Section: Resultsmentioning

confidence: 99%

Simulating electric field interactions with polar molecules using spectroscopic databases

Owens

Żak

Chubb

et al. 2017

Sci Rep

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Ro-vibrational Stark-associated phenomena of small polyatomic molecules are modelled using extensive spectroscopic data generated as part of the ExoMol project. The external field Hamiltonian is built from the computed ro-vibrational line list of the molecule in question. The Hamiltonian we propose is general and suitable for any polar molecule in the presence of an electric field. By exploiting precomputed data, the often prohibitively expensive computations associated with high accuracy simulations of molecule-field interactions are avoided. Applications to strong terahertz field-induced ro-vibrational dynamics of PH3 and NH3, and spontaneous emission data for optoelectrical Sisyphus cooling of H2CO and CH3Cl are discussed.

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Section: Resultsmentioning

confidence: 99%

Simulating electric field interactions with polar molecules using spectroscopic databases

Owens

Żak

Chubb

et al. 2017

Sci Rep

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“…The ab initio prediction for the  6 band intensity [17] is about twice as large as the experimental values [14,15]. However, recent computations performed for CH 3 Cl [34,35] clearly indicate that the quality of ab initio predictions was significantly improved since 1987.…”

Section: F Validation Of the Line Intensity Calculationmentioning

confidence: 92%

Line intensities for the ν6 and 2ν3 bands of methyl iodide (12CH3I)

Kwabia-Tchana

Attafi

Manceron

et al. 2019

Journal of Quantitative Spectroscopy and Radiative Transfer

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The goal of this study is to measure for the first time absolute line intensities for the ν 6 band of methyl iodide (CH 3 I) centered at 892.918 cm-1. High-resolution Fourier transform spectra were recorded at various pressures for the whole 500-1450 cm-1 spectral range. Using these spectra, a large set of CH 3 I individual line intensities was measured for the  6 band. These experimental intensities were least squares fitted to derive the expansion of the  6 transition moment operator. The theoretical model used to describe the line positions and intensities accounts for the hyperfine structure in the 6 1 and ground states and for the vibration-rotation resonances that couple the 6 1 energy levels with those of the 3 2 and 2 1 vibrational states [A. Perrin et al., J. Mol. Spectrosc. 324 (2016) 28-35]. As the 2 3 band is extremely weak, its associated transition moment operator was estimated from band strength available in the literature. A comprehensive list of line positions and intensities was generated for the  6 and 2 3 bands of CH 3 I at 11 µm, which should be useful for the possible detection of this species by the future IASI-NG satellite instrument (Infrared Atmospheric Sounding Interferometer New Generation), now under preparation (https://iasi-ng.cnes.fr/en/IASI-NG/index.htm).

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“…The analytic representation used for the DMS of methyl fluoride was previously employed for CH 3 Cl and the reader is referred to Owens et al 52 for a detailed description. To begin with, it is necessary to transform to a suitable molecule-fixed xyz coordinate system before fitting an analytic expression to the ab initio data.…”

Section: B Analytic Representationmentioning

confidence: 99%

“…Its construction is slightly more complex because µ is a vector quantity and the transformation properties of the dipole moment components must also be considered. 52 The expansion parameter set of the DMS is given in the electronic supplementary information along with a Fortran routine to construct the analytic representation.…”

Section: B Analytic Representationmentioning

confidence: 99%

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The rotation–vibration spectrum of methyl fluoride from first principles

Owens

Yachmenev

Küpper

et al. 2019

Phys. Chem. Chem. Phys.

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Accurate ab initio calculations on the rotation-vibration spectrum of methyl fluoride (CH3F) 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 CH3F, vibrational transition moments, absolute line intensities of the ν6 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 CH3F to date.

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A global ab initio dipole moment surface for methyl chloride

Cited by 15 publications

References 78 publications

Simulating electric field interactions with polar molecules using spectroscopic databases

Simulating electric field interactions with polar molecules using spectroscopic databases

Line intensities for the ν6 and 2ν3 bands of methyl iodide (12CH3I)

The rotation–vibration spectrum of methyl fluoride from first principles

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