Line positions, intensities and self-broadening coefficients for the ν5 band of methyl chloride

Ramchani, A. Barbouchi; Jacquemart, D.; Dhib, M.; Aroui, H.

doi:10.1016/j.jqsrt.2013.02.002

Cited by 23 publications

(31 citation statements)

References 46 publications

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“…8 The 6.9 µm region has seen line positions, intensities, and self-broadening coefficients determined for more than 900 rovibrational transitions of the ν 5 band. 23 Nikitin et al have also measured, modelled, and assigned over 20 000 transitions for each isotopologue in the region of 0-2600 cm −1 . [28][29][30][31] An effective Hamiltonian model adapted to the polyad structure of methyl chloride reproduced observed transitions involving the ground state and 13 vibrational states with an overall standard deviation of 0.0003 cm −1 .…”

Section: Introductionmentioning

confidence: 99%

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Accurate ab initio vibrational energies of methyl chloride

Owens

Yurchenko

Yachmenev

et al. 2015

The Journal of Chemical Physics

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Two new nine-dimensional potential energy surfaces (PESs) have been generated using high-level ab initio theory for the two main isotopologues of methyl chloride, CH3 (35)Cl and CH3 (37)Cl. The respective PESs, CBS-35( HL), and CBS-37( HL), are based on explicitly correlated coupled cluster calculations with extrapolation to the complete basis set (CBS) limit, and incorporate a range of higher-level (HL) additive energy corrections to account for core-valence electron correlation, higher-order coupled cluster terms, scalar relativistic effects, and diagonal Born-Oppenheimer corrections. Variational calculations of the vibrational energy levels were performed using the computer program TROVE, whose functionality has been extended to handle molecules of the form XY 3Z. Fully converged energies were obtained by means of a complete vibrational basis set extrapolation. The CBS-35( HL) and CBS-37( HL) PESs reproduce the fundamental term values with root-mean-square errors of 0.75 and 1.00 cm(-1), respectively. An analysis of the combined effect of the HL corrections and CBS extrapolation on the vibrational wavenumbers indicates that both are needed to compute accurate theoretical results for methyl chloride. We believe that it would be extremely challenging to go beyond the accuracy currently achieved for CH3Cl without empirical refinement of the respective PESs.

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Section: Introductionmentioning

confidence: 99%

“…We refer the reader to the most recent publications 8,[15][16][17][18][19][20][21][22][23][24][25][26][27][28][29][30][31][32] (and references therein) for a more complete overview.…”

Section: Introductionmentioning

confidence: 99%

Accurate ab initio vibrational energies of methyl chloride

Owens

Yurchenko

Yachmenev

et al. 2015

The Journal of Chemical Physics

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“…band [14]. These two studies are the most reliable and complete line intensity measurements for both CH 3 35 Cl and CH 3 37 Cl to date.…”

Section: Introductionmentioning

confidence: 74%

“…Here, |Φ Transition moments have been determined experimentally for the six fundamental modes of CH 3 35 Cl and these are listed in Table 1 Recently, absolute line intensities were determined for the ν 1 , ν 4 and 3ν 6 bands around the 3.4 µm region [4] (included in HITRAN2012), and for the ν 5 band in the 6.9 µm region [14]. To assess the DMS we compare against these works for both isotopologues up to J = 15.…”

Section: Vibrational Transition Momentsmentioning

confidence: 99%

“…Some line positions and intensities are also from theoretical predictions using a fairly old, empirically refined anharmonic force field [33]. Given the numerous high-resolution studies since then, notably in the 3.4 µm region [4] (included in HITRAN2012) and in the 6.9 µm region [14], improvements can be expected in the coverage of CH 3 Cl. Another valuable resource is the PNNL spectral library [34] which covers the 600 to 6500 cm −1 region at a resolution of around 0.06 cm −1 for temperatures of 5, 25 and 50 • C. Other databases such as GEISA [35] include CH 3 Cl but the datasets are not as extensive, whilst the JPL [36] catalog has been incorporated into HITRAN.…”

Section: Introductionmentioning

confidence: 99%

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A global ab initio dipole moment surface for methyl chloride

Owens

Yurchenko

Yachmenev

et al. 2016

Journal of Quantitative Spectroscopy and Radiative Transfer

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A new dipole moment surface (DMS) for methyl chloride has been generated at the CCSD(T)/aug-cc-pVQZ(+d for Cl) level of theory. To represent the DMS, a symmetry-adapted analytic representation in terms of nine vibrational coordinates has been developed and implemented. Variational calculations of the infrared spectrum of CH₃Cl show good agreement with a range of experimental results. This includes vibrational transition moments, absolute line intensities of the ν₁, ν₄, ν₅ and 3ν₆ bands, and a rotation–vibration line list for both CH₃³⁵Cl and CH₃³⁷Cl including states up to J=85 and vibrational band origins up to 4400 cm⁻¹. Across the spectrum band shape and structure are well reproduced and computed absolute line intensities are comparable with highly accurate experimental measurements for certain fundamental bands. We thus recommend the DMS for future use

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