Ideal gas thermodynamic properties of the eight bromo- and lodomethanes

Kudchadker, Shanti A.; Kudchadker, Arvind P.

doi:10.1063/1.555522

Cited by 52 publications

(42 citation statements)

References 32 publications

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“…For methyl iodide CH 3 I, the thermodynamic functions from Table 6 and those previously calculated in [27] differ in the second or third digit at medium temperatures, and in the second and even first digit at T > 1000 K. For the remaining iodomethanes (CH 2 I 2 , CHI 3 , and CI 4 ), our data (Table 6) and those from [27] differ in the first or second digit. As to CH 2 I .…”

Section: äääääääääääáäääääääáäääääääääääääáääääääääääääáääääääääääääámentioning

confidence: 42%

“…The last three rows in Table 4 show that all these products for all the iodomethanes are systematically underestimated by 5310% [26] and 10320% [27]. For the CI .…”

Section: äääääääääääáäääääääáäääääääääääääáääääääääääääáääääääääääääámentioning

confidence: 99%

“…3 molecules were obtained by rigorous calculation, rather than by analogy or extrapolation methods to which the authors of fundamental works [26,27] had to confine themselves. It is essential that the normal mode frequencies yielded by our ab initio calculations do not require further multiplication by a scaled factor, by contrast to the previous studies [6,10,11] which neglect intramolecular electron correlations.…”

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Molecular, thermodynamic, and kinetic parameters of iodomethanes and iodomethyl radicals: ab initio calculations

2004

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The wave functions and enthalpies of formation of the ground states of iodomethanes CH 4 3x I x and iodomethyl radicals CH 3 3x I x . (x = 133) were calculated ab initio with regard to electron correlation. The geometries of the molecules of these compounds were determined, as well as the normal mode frequencies and other parameters, which were used for calculating the thermodynamic functions in the 031500 K range.These functions were used for calculating the constants of the CH 4 3x I x 76 47 CH 4 3x I x 31 + I and CH 4 3x I x + I 76 47 CH 4 3x I x 31 + I 2 equilibria, which, in turn, were used for calculating the corresponding rate constants in the high concentration limit.Studies of gas-phase pyrolysis of alkyl halides have been successfully used in developing fundamentals of chemical kinetics for almost a century [1,2]. The key reactions for the alkyl halides being pyrolyzed are those between (halo)alkyl radical and atomic hydrogen: R . + H . 76 RH, halogen: R . + Hlg . 76 RHlg, or hydrogen halide molecules: R . + HHlg 76 RH + Hlg . , Hlg = Cl, Br, I.Hence, these pyrolytic experiments furnish kinetic and thermochemical information about free radicals [336]. For the last-named reactions (CH 3 . + HI, CH 3 . + HBr, C 2 H 5 . + HBr, CH 2 Br . + HI...), peculiar phenomenon of a negative activation energy was recently discovered [739], whose nature still remains to be elucidated [10313]. Accurate thermodynamic and kinetic parameters of chloro-, bromo-, and iodoalkanes and their corresponding radicals are also essential for solving less fundamental but practically vital problems, such as, e.g., simulation of the Earth ozone layer depletion or modeling of incineration of halogencontaining waste.

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Section: äääääääääääáäääääääáäääääääääääääáääääääääääääáääääääääääääámentioning

confidence: 42%

“…The last three rows in Table 4 show that all these products for all the iodomethanes are systematically underestimated by 5310% [26] and 10320% [27]. For the CI .…”

Section: äääääääääääáäääääääáäääääääääääääáääääääääääääáääääääääääääámentioning

confidence: 99%

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Molecular, thermodynamic, and kinetic parameters of iodomethanes and iodomethyl radicals: ab initio calculations

2004

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“…42, 43 The calculated C-I bond lengths of CH 2 BrI and CH 2 I 2 are longer than the available CASPT2 results.…”

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confidence: 82%

Spin-orbit Effects on the Structure of Haloiodomethane Cations CH₂XI⁺(X=F, Cl, Br, and I)

Kim¹,

Park²,

Lee³

2014

Bulletin of the Korean Chemical Society

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The importance of including spin-orbit interactions for the correct description of structures and vibrational frequencies of haloiodomethanes is demonstrated by density functional theory calculations with spin-orbit relativistic effective core potentials (SO-DFT). The vibrational frequencies and the molecular geometries obtained by SO-DFT calculations do not match with the experimental results as well as for other cations without significant relativistic effects. In this sense, the present data can be considered as a guideline in the development of the relativistic quantum chemical methods. The influence of spin-orbit effects on the bending frequency of the cation could well be recognized by comparing the experimental and calculated results for CH 2 BrI and CH 2 ClI cations. Spin-orbit effects on the geometries and vibrational frequencies of CH 2 XI (X=F, Cl, Br, and I) neutral are negligible except that C-I bond lengths of haloiodomethane neutral is slightly increased by the inclusion of spin-orbit effects. The A'' states were found in the cations of haloiodomethanes and mix due to the spin-orbit interactions and generate two 2 E 1/2 fine-structure states. The geometries of CH 2 XI + (X=F and Cl) from SO-DFT calculations are roughly in the middle of two cation geometries from DFT calculations since two cation states of CH 2 XI (X=F and Cl) from DFT calculations are energetically close enough to mix two cation states. The geometries of CH 2 XI + (X=Br and I) from SO-DFT calculations are close to that of the most stable cation from DFT calculations since two cation states of CH 2 XI (X=Br and I) from DFT calculations are energetically well separated near the fine-structure state minimum.

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“…Energetic values obtained for both pathways are given in Table 3, together with experimental reaction enthalpies obtained from available enthalpies of formation for each species [43][44][45][46][47][48][49]. Key stationary point structures, namely PRE, TS1, TS2 and POST2, are presented in Fig.…”

Section: Minimum Energy Paths For (R1) and (R2) Channelsmentioning

confidence: 99%

Theoretical kinetic study of the CH3Br+OH atmospheric system

et al. 2006

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Ideal gas thermodynamic properties of the eight bromo- and lodomethanes

Abstract: Erratum: Ideal gas thermodynamic properties of eight Bromo− and Iodomethanes

Cited by 52 publications

References 32 publications

Molecular, thermodynamic, and kinetic parameters of iodomethanes and iodomethyl radicals: ab initio calculations

Molecular, thermodynamic, and kinetic parameters of iodomethanes and iodomethyl radicals: ab initio calculations

Spin-orbit Effects on the Structure of Haloiodomethane Cations CH₂XI⁺(X=F, Cl, Br, and I)

Theoretical kinetic study of the CH3Br+OH atmospheric system

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Ideal gas thermodynamic properties of the eight bromo- and lodomethanes

Abstract: Erratum: Ideal gas thermodynamic properties of eight Bromo− and Iodomethanes

Cited by 52 publications

References 32 publications

Molecular, thermodynamic, and kinetic parameters of iodomethanes and iodomethyl radicals: ab initio calculations

Molecular, thermodynamic, and kinetic parameters of iodomethanes and iodomethyl radicals: ab initio calculations

Spin-orbit Effects on the Structure of Haloiodomethane Cations CH2XI+(X=F, Cl, Br, and I)

Theoretical kinetic study of the CH3Br+OH atmospheric system

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Spin-orbit Effects on the Structure of Haloiodomethane Cations CH₂XI⁺(X=F, Cl, Br, and I)