Infrared Spectra of12CF2═12CH2and12CF2═13CH2, Quantum-Chemical Calculations of Anharmonicity, and Analyses of Resonances

McKean, D.C.; Veken, B. Van der; Herrebout, Wouter A.; Law, Mark M.; Brenner, Michael; Nemchick, Deacon J.; Craig, Norman C.

doi:10.1021/jp100438z

Cited by 17 publications

(37 citation statements)

References 25 publications

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“…Subsequently, Mann et al, on the basis of the assignments available at their time for the CH 2 stretchings of 1,1-difluoroethene and 1,1-dichloroethene, suggested the positions centered at 3069 and 3016 cm –1 for ν 1 and ν 2 , respectively. Concerning 1,1-difluoroethene, the CH 2 stretching bands were definitely located at 3175.6 cm –1 (ν 7 , antisymmetric) and 3057.8 cm –1 (ν 1 , symmetric) by McKean et al, thus revising the value of 3103 cm –1 previously accepted for the antisymmetric CH 2 stretching; subsequently, these values were found to be in agreement with the predictions yielded by high-level theoretical computations . All our harmonic calculations carried out at CCSD(T) level of theory yielded values around 3300 and 3200 cm –1 for the antisymmetric (ν 1 ) and symmetric (ν 2 ) CH 2 stretchings, respectively (see Table ).…”

Section: Results and Analysissupporting

confidence: 87%

“…Being considered trace gas pollutants, the kinetics of their reactions with O( 3 P), and their photochemistry , and adsorption − on substrates suitable for subsequent photodegradation have also been investigated. For supporting the monitoring by means of spectroscopic techniques studies dealing with the computation of the vibrational frequencies, the analysis of resonances and determination of anharmonic constants from the assignments of low-resolution infrared spectra have been carried out for some halogenated ethenes. − …”

Section: Introductionmentioning

confidence: 99%

“…Nevertheless, the only available data on the vibrational assignment date back to the low-resolution infrared and Raman investigations reported a long time ago. − In these studies, besides ambiguities in the interpretation of the spectral features derived from the presence of many signals due to impurities, the proposed assignment of the bands was carried out mainly by correlating them with the positions of the fundamentals which, at that time, were assigned for CH 2 CF 2 and CH 2 CCl 2 . It is worthwhile to note that for 1,1-difluoroethene, especially the origins of both the antisymmetric and symmetric CH 2 stretchings, the assignments were revised and later definitely reassigned …”

Section: Introductionmentioning

confidence: 99%

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Study of the Vibrational Spectra and Absorption Cross Sections of 1-Chloro-1-fluoroethene by a Joint Experimental and Ab Initio Approach

et al. 2016

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The gas-phase infrared spectra of 1-chloro-1-fluoroethene (geminal chloro-fluoroethene, ClFC=CH, 1,1-CHClF) were recorded at medium resolution in the range 400 - 6400 cm and the vibrational analysis led to revise the previous assignments for the ν (A'' symmetry), ν (A' symmetry) and ν (A' symmetry) bands. Besides the fundamentals, all the most relevant spectral features were interpreted in terms of overtone and combination bands, thus obtaining an accurate description of the vibrational structure of ClFC=CH2. Accurate measurements of absorption cross section spectra were carried out and integrated band intensity data were determined. High-level ab initio calculations of harmonic and anharmonic force fields thoroughly supported and guided the analysis and the disentangling of the several strongly coupled polyads involving many vibrational levels. Diagonalization of the effective Hamiltonian with the off-diagonal elements involving several Fermi and Darling-Dennison resonance coefficients computed by the theoretical cubic and quartic force constants provided the predicted energy levels in good agreement with the vibrational assignments. The calculated infrared intensities, obtained by taking into account anharmonic corrections, were compared to the accurate experimental absorption cross section data here determined.

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Section: Results and Analysissupporting

confidence: 87%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Study of the Vibrational Spectra and Absorption Cross Sections of 1-Chloro-1-fluoroethene by a Joint Experimental and Ab Initio Approach

et al. 2016

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“…2,3 Moreover, vibrational analysis of their experimental data 3 was supported by theoretical predictions including anharmonic effects. [4][5][6][7][8][9][10] Among a large number of currently used density functionals 37 for practical reasons we selected B3LYP [38][39][40] and BLYP [39][40][41] for structural and vibrational calculations. The first one, in combination with medium and large size basis sets including polarization and diffuse functions, is very efficient (and widely used) in predicting various parameters in all kinds of small and medium size molecules.…”

Section: Introductionmentioning

confidence: 99%

Theoretical prediction of nuclear magnetic shieldings and indirect spin-spin coupling constants in 1,1-, cis-, and trans-1,2-difluoroethylenes

Nozirov

Kupka²,

Stachów

2014

The Journal of Chemical Physics

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A theoretical prediction of nuclear magnetic shieldings and indirect spin-spin coupling constants in 1,1-, cis- and trans-1,2-difluoroethylenes is reported. The results obtained using density functional theory (DFT) combined with large basis sets and gauge-independent atomic orbital calculations were critically compared with experiment and conventional, higher level correlated electronic structure methods. Accurate structural, vibrational, and NMR parameters of difluoroethylenes were obtained using several density functionals combined with dedicated basis sets. B3LYP/6-311++G(3df,2pd) optimized structures of difluoroethylenes closely reproduced experimental geometries and earlier reported benchmark coupled cluster results, while BLYP/6-311++G(3df,2pd) produced accurate harmonic vibrational frequencies. The most accurate vibrations were obtained using B3LYP/6-311++G(3df,2pd) with correction for anharmonicity. Becke half and half (BHandH) density functional predicted more accurate (19)F isotropic shieldings and van Voorhis and Scuseria's τ-dependent gradient-corrected correlation functional yielded better carbon shieldings than B3LYP. A surprisingly good performance of Hartree-Fock (HF) method in predicting nuclear shieldings in these molecules was observed. Inclusion of zero-point vibrational correction markedly improved agreement with experiment for nuclear shieldings calculated by HF, MP2, CCSD, and CCSD(T) methods but worsened the DFT results. The threefold improvement in accuracy when predicting (2)J(FF) in 1,1-difluoroethylene for BHandH density functional compared to B3LYP was observed (the deviations from experiment were -46 vs. -115 Hz).

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“…Within this framework, several investigations (see, for example, refs. [ 23 , 24 , 25 , 26 , 27 , 28 , 29 ] and references therein) have been carried out to disentagle the anharmonic interactions in their vibrational spectra and to assess the quality of the predicted dipole moment surfaces against the spectroscopic experimental data.…”

Section: Introductionmentioning

confidence: 99%

The Spectroscopic Characterization of Halogenated Pollutants through the Interplay between Theory and Experiment: Application to R1122

et al. 2022

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In the last decade, halogenated ethenes have seen an increasing interest for different applications; in particular, in refrigeration, air-conditioning and heat pumping. At the same time, their adverse effects as atmospheric pollutants require environmental monitoring, especially by remote sensing spectroscopic techniques. For this purpose, an accurate characterization of the spectroscopic fingerprint—in particular, those of relevance for rotational–vibrational spectroscopy—of the target molecules is strongly needed. This work provides an integrated computational–theoretical investigation on R1122 (2-Chloro-1,1-difluoro-ethylene, ClHC=CF2), a compound widely employed as a key intermediate in different chemical processes. State-of-the-art quantum chemical calculations relying on CCSD(T)-based composite schemes and hybrid CCSD(T)/DFT approaches are used to obtain an accurate prediction of the structural, rotational and vibrational spectroscopic properties. In addition, the equilibrium geometry is obtained by exploiting the semi-experimental method. The theoretical predictions are used to guide the analysis of the experimentally recorded gas-phase infrared spectrum, which is assigned in the 400–6500 cm−1 region. Furthermore, absorption cross sections are accurately determined over the same spectral range. Finally, by using the obtained spectroscopic data, a first estimate of the global warming potential of R1122 vibrational spectra is obtained.

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Infrared Spectra of¹²CF₂═¹²CH₂and¹²CF₂═¹³CH₂, Quantum-Chemical Calculations of Anharmonicity, and Analyses of Resonances

Cited by 17 publications

References 25 publications

Study of the Vibrational Spectra and Absorption Cross Sections of 1-Chloro-1-fluoroethene by a Joint Experimental and Ab Initio Approach

Study of the Vibrational Spectra and Absorption Cross Sections of 1-Chloro-1-fluoroethene by a Joint Experimental and Ab Initio Approach

Theoretical prediction of nuclear magnetic shieldings and indirect spin-spin coupling constants in 1,1-, cis-, and trans-1,2-difluoroethylenes

The Spectroscopic Characterization of Halogenated Pollutants through the Interplay between Theory and Experiment: Application to R1122

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