Infrared vibrational intensities and polar tensors of CF 3 Br and CF 3 I

Filho, Harley Paiva Martins; Guadagnini, Paulo H.

doi:10.1016/s0166-1280(98)00549-1

Cited by 10 publications

(4 citation statements)

References 21 publications

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“…Nitrogen, oxygen, fluorine, phosphorus, chlorine, and boron 1s electron ionization energies were taken from the collection of X-ray ionization energies published by Jolly and co-workers NH 3 and PH 3 ; NF 3 and PF 3 ; HCN, C 2 N 2 , and CH 3 CN; NO, CO, NaF, LiF, HCl, and HF; F 2 CO and Cl 2 CO; H 2 CO; Br 2 CO; SiF 4 ; F 2 CS; CHF 3 , CH 2 F 2 , CH 3 F, CH 3 Cl, CH 2 Cl 2 , and CHCl 3 ; CF 3 Cl, CF 2 Cl 2 , and CFCl 3 ; cis -C 2 H 2 Cl 2 ; CCl 4 ; ClCN, BrCN, N 2 O, OCS, and CO 2 ; C 6 F 6 ; 1,1-C 2 H 2 F 2 ; and CF 3 I …”

Section: Calculationsmentioning

confidence: 99%

“…8 Mean dipole moment derivatives obtained from experimental infrared intensity data and used here have been reported by a number of research groups: BF 3 and BCl 3 ; 9 NH 3 and PH 3 ; 10 NF 3 and PF 3 ; 11 HCN, C 2 N 2 , and CH 3 CN; 12 NO, CO, NaF, LiF, HCl, and HF; 13 F 2 CO and Cl 2 CO; 14 H 2 CO; 15 19 ClCN, BrCN, N 2 O, OCS, and CO 2 ; 20 C 6 F 6 ; 21 1,1-C 2 H 2 F 2 ; 22 and CF 3 I. 23 Within the harmonic oscillator-linear dipole moment approximations the measured fundamental infrared intensity, A i , is proportional to the square of the dipole moment derivative with respect to its associated normal coordinate, Q i with N A and c being Avogadro's number and the velocity of light. 24 The dipole moment derivatives can be transformed to atomic Cartesian coordinates using the expression 25,26 where P Q is a 3 × 3N -6 matrix of dipole moment derivatives obtained from measured infrared intensities and L -1 , U, and B are well-known transformation matrixes commonly used in normal coordinate analysis.…”

Section: Calculationsmentioning

confidence: 99%

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Core Ionization Energies, Mean Dipole Moment Derivatives, and Simple Potential Models for B, N, O, F, P, Cl, and Br Atoms in Molecules

2002

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Simple potential models relating experimental 1s electron ionization energies for B, N (sp and sp3 hybrids), O, and F atoms; 1s and 2p ionization energies for P atoms; and 2s and 2p ionization energies for Cl atoms as a function of their atomic mean dipole moment derivatives determined from experimental gas phase infrared fundamental band intensities are reported. Potential models using theoretical Koopmans' energies and generalized atomic polar tensor (GAPT) charges are found to form even more precise models than those using experimental data. This is expected because the potential models depend only on the electronic structures of molecules before ionization takes place and do not take into account relaxation effects. If the experimental ionization energies are adjusted by their relaxation energies, models similar to those obtained using Koopmans' energies are determined. The models permit a simple understanding of substituent effects on core ionization energies in terms of atomic charges in molecules. Most of the potential model slopes investigated are shown to be approximately proportional to the inverse atomic radii of the atom being ionized. Core-valence electron repulsion values inferred from the potential models obtained from experimental data are somewhat smaller than those calculated using Slater orbitals of isolated atoms. The potential model intercepts for 1s and 2p electrons are shown to be proportional to the square of the nuclear charge, consistent with their interpretation as core electron ionization energies of neutral atoms. 1s He, Ne, and Ar and 2p Ar, Kr, and Xe core ionization energies obey the linear relationships obtained for the model intercepts. The results suggest that mean dipole moment derivatives obtained from infrared intensities can be interpreted as atomic charges.

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Section: Calculationsmentioning

confidence: 99%

Section: Calculationsmentioning

confidence: 99%

Core Ionization Energies, Mean Dipole Moment Derivatives, and Simple Potential Models for B, N, O, F, P, Cl, and Br Atoms in Molecules

2002

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“… a The polar vibrational states are indicated as . b Anharmonic calculations performed with the JnDZ basis set based on a set of harmonic frequencies evaluated with the JnTZ basis set. c Anharmonic calculations performed at the MP2/JnDZ level based on a set of harmonic frequencies evaluated at the CCSD(T)/aug-cc-pVTZ-PP level. d Reference . e Reference . f Reference . g Reference . …”

Section: Resultsmentioning

confidence: 99%

General Perturb-Then-Diagonalize Model for the Vibrational Frequencies and Intensities of Molecules Belonging to Abelian and Non-Abelian Symmetry Groups

Mendolicchio

Bloino

Barone

2021

J. Chem. Theory Comput.

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In this paper, we show that the standard second-order vibrational perturbation theory (VPT2) for Abelian groups can be used also for non-Abelian groups without employing specific equations for twoor threefold degenerate vibrations but rather handling in the proper way all the degeneracy issues and deriving the peculiar spectroscopic signatures of non-Abelian groups (e.g., -doubling) by a posteriori transformations of the eigenfunctions. Comparison with the results of previous conventional implementations shows a perfect agreement for the vibrational energies of linear and symmetric tops, thus paving the route to the transparent extension of the equations already available for asymmetric tops to the energies of spherical tops and the infrared and Raman intensities of molecules belonging to non-Abelian symmetry groups. The whole procedure has been implemented in our general engine for vibrorotational computations beyond the rigid rotor/harmonic oscillator model and has been validated on a number of test cases.

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“…Experimental 1s ionization energies and carbon mean dipole-moment derivatives ,, determined from infrared intensities are presented in Table for the fluorochloromethanes and a variety of other molecules including some with sp- and sp 2 -hybridized carbon atoms. These values were used to calculate carbon core electron ionization energies and mean dipole-moment derivatives of selected molecules using equations analogous to eq 2.…”

Section: Resultsmentioning

confidence: 99%

Characteristic Substituent-Shift Models for Carbon 1s Ionization Energies and Mean Dipole-Moment Derivatives

et al. 2004

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Characteristic substituent-shift models for carbon mean dipole-moment derivatives are determined for the halomethanes, fluorochloroethanes, and some other small molecules. These models are analogous to those reported earlier for core ionization energies measured by X-ray photoelectron spectroscopy and are to be expected since Siegbahn's simple potential model relates these to mean dipole-moment derivatives obtained from infrared spectral data. Linear models relating carbon 1s ionization energies and mean dipole-moment derivatives to the number of fluorine, chlorine, bromine, and iodine atoms substituting hydrogen atoms in the halomethanes are reported. The regression coefficients in these models are similar to the coefficients for the fluorine and chlorine atoms found in linear models derived for the mean dipole-moment derivatives and carbon 1s ionization energies of the fluorochloroethanes. The signs of the coefficients in the fluorochloroethane model indicate that the R carbon becames more positive and the carbon more negative upon fluorine substitution for hydrogen. Standard derivative values of -0.52 ( 0.05, -0.25 ( 0.05, -0.18 ( 0.03, -0.17 ( 0.03, and -0.01 ( 0.01 e are proposed for the fluorine, chlorine, bromine, iodine, and hydrogen atoms of saturated fluorochlorohydrocarbons. Characteristic substituent shifts for Mulliken, CHELPG, and Bader charges of the carbon atoms in these molecules are also investigated.

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Infrared vibrational intensities and polar tensors of CF 3 Br and CF 3 I

Cited by 10 publications

References 21 publications

Core Ionization Energies, Mean Dipole Moment Derivatives, and Simple Potential Models for B, N, O, F, P, Cl, and Br Atoms in Molecules

Core Ionization Energies, Mean Dipole Moment Derivatives, and Simple Potential Models for B, N, O, F, P, Cl, and Br Atoms in Molecules

General Perturb-Then-Diagonalize Model for the Vibrational Frequencies and Intensities of Molecules Belonging to Abelian and Non-Abelian Symmetry Groups

Characteristic Substituent-Shift Models for Carbon 1s Ionization Energies and Mean Dipole-Moment Derivatives

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