The General Harmonic Force Field of Methyl Chloride

Black, G. M.; Law, Mark M.

doi:10.1006/jmsp.2000.8275

Cited by 22 publications

(7 citation statements)

References 29 publications

(20 reference statements)

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“…Mössbauer-based fractionation models are based on an extension of Equations (4) and (5) (Bigeleisen and Mayer 1947), which relate to either sums of squares of vibrational frequencies or a sum of force constants. In the Polyakov (1997) (Black and Law 2001) and ab initio vibrational frequencies for methyl chloride, 12 C 1 H 3 35 Cl. Ab initio frequencies are calculated with GAMESS, using the Hartree-Fock method and 6-31G(d) basis set.…”

Section: Theoretical Applications Of Mössbauer Spectroscopymentioning

confidence: 99%

Applying Stable Isotope Fractionation Theory to New Systems

Schauble

2004

Reviews in Mineralogy and Geochemistry

603

358

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Section: Theoretical Applications Of Mössbauer Spectroscopymentioning

confidence: 99%

Applying Stable Isotope Fractionation Theory to New Systems

Schauble

2004

Reviews in Mineralogy and Geochemistry

603

358

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“…Much attention has been given to a description of harmonic [33][34][35][36][37][38][39][40] and anharmonic 9,41-46 force fields, both empirically and using ab initio methods. The latest work by Black and Law 40 employed spectroscopic data from ten isotopomers of methyl chloride to produce an empirical harmonic force field incorporating the most up to date treatment of anharmonic corrections. These were largely based on a complete set of empirical anharmonicity constants derived from a joint local mode and normal mode analysis of 66 vibrational energy levels in the region of 700-16 500 cm −1 , 45 and follow-up work in a similar vein by Law.…”

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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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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“…Wavenumber a Reference Differently from the parent species CH 3 Cl (C 3v group), in which the carbonhalogen bond lies on the symmetry axis, the a-axis of the principal inertia system of CH 2 DCl is slightly rotated with the respect to the C -Cl bond because of the different center of mass. Replacing one hydrogen atom with deuterium causes the permanent dipole moment (µ = 1.870 D for CH 3 Cl [32]) to be distributed along two components; based on geometric considerations [33], and assuming that the total dipole moment does not change among the isotopologues, one can estimate µ a = 1.868 D and µ b = 0.076 D for CH 2 DCl. The rotational energy of CH 2 DCl can be modeled by using the standard semirigid Hamiltonian for an asymmetric rotor with a non-vanishing nuclear spin:…”

Section: Symmetry Mode Descriptionmentioning

confidence: 99%

High-resolution millimeter-wave spectroscopy of CH2DCl: Paving the way for future astronomical observations of chloromethane isotopologues

Melosso

Achilli

Tamassia

et al. 2020

Journal of Quantitative Spectroscopy and Radiative Transfer

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Chloromethane is the only organochloride detected in space to date. Its recent observation towards the low-mass protostar IRAS 16293-2422 with ALMA offers a prompt for new laboratory studies of CH 3 Cl and its isotopologues. Here, we report the investigation of the rotational spectrum of monodeuterated chloromethane CH 2 DCl in the frequency region between 90 and 300 GHz. The measurements have been carried out with a frequency-modulation millimeterwave spectrometer, arranged to perform saturation spectroscopy. From the analysis of hyperfine-resolved spectra of the two chlorine isotopologues CH 2 D 35 Cl and CH 2 D 37 Cl, consistent sets of accurate spectroscopic parameters have been obtained. This work provides reliable spectral predictions which can be used to guide radio-astronomical searches of CH 2 DCl in the interstellar medium and represents a solid base for future analyses of high-resolution infrared spectra of monodeuterated chloromethane.

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The General Harmonic Force Field of Methyl Chloride

Cited by 22 publications

References 29 publications

Applying Stable Isotope Fractionation Theory to New Systems

Applying Stable Isotope Fractionation Theory to New Systems

Accurate ab initio vibrational energies of methyl chloride

High-resolution millimeter-wave spectroscopy of CH2DCl: Paving the way for future astronomical observations of chloromethane isotopologues

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