Electronic and relaxation contribution to linear molecular polarizability. An analysis of the experimental values

Gussoni, M.; Rui, Marina; Zerbi, G.

doi:10.1016/s0022-2860(97)00292-5

Cited by 134 publications

(93 citation statements)

References 132 publications

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“…Increasing the oligomer length certainly increases the conjugation length, but also the intermolecular interactions increase as a consequence of the superlinear increase of the molecular polarizability with chain lengths. 32 Thus, when comparing oligomers with different chain lengths at a given temperature we are comparing systems which feel "different'' intermolecular environments. In a first approximation, directional VdW interactions can be taken as vanishing as close as possible to the melting point.…”

Section: Comparison Between Theoretical and Experimental Resultsmentioning

confidence: 99%

Raman Dispersion and Intermolecular Interactions in Unsubstituted Thiophene Oligomers

et al. 2007

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We present a critical analysis of the Raman spectra of unsubstituted oligothiophenes and rediscuss the well-known Raman dispersion of conjugated systems explicitly considering intermolecular interactions. Temperature-dependent Raman spectra and DFT calculations for dimers of different chain lengths show that the effect of intermolecular interactions on the frequency and intensity of carbon-carbon (CC) stretching modes is non-negligible. This effect has not been considered in previous works and might explain many spectral features of this class of compounds which are not completely interpreted by the usual models. Both intensities and frequencies are significantly affected by intermolecular interactions showing that molecular self-organization should be taken into account in future spectroscopic studies of conjugated molecules. In particular, the interactions among molecules cause an upward shift of the frequency of the R mode (amplitude mode) which can explain the lack of frequency dispersion with conjugation length of oligothiophenes, as experimentally observed for solid-state samples at room temperature.

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Section: Comparison Between Theoretical and Experimental Resultsmentioning

confidence: 99%

Raman Dispersion and Intermolecular Interactions in Unsubstituted Thiophene Oligomers

et al. 2007

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“…The experimentally determined ionisation energy of the system is 9.9 eV 38 and its experimental polarizability is 11.23 Å 3 . 39 The description of core-excited resonances requires inclusion of electronic excited states in the scattering calculation. These excited states have been extensively studied in p-BQ using theoretical methods.…”

Section: Characteristics Of the Calculationmentioning

confidence: 99%

Resonances in low-energy electron scattering from para-benzoquinone

Loupas

Gorfinkiel

2017

Phys. Chem. Chem. Phys.

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We present detailed ab initio scattering calculations for electron collisions with parabenzoquinone. The R-Matrix method has been used to study elastic and electronically inelastic scattering. We have identified 26 resonances of Feshbach, core-excited shape and mixed character between 0 and 8 eV. Agreement of our resonance spectrum with existing literature is discussed, in particular that of the low-lying resonances that participate in the photodetachment process. Integral elastic and total inelastic cross sections are also presented.

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“…Experimentally the mean value ) ( 3 1 zz yy xx α + α + α = > α < is usually determined from the refractive index or from dielectric measurements [2], while α v can be obtained from infrared intensities [2][3][4]. Theoretically <α> can be obtained accurately by means of Density Functional Theory (DFT) and wave function-based methods, provided that sufficiently flexible basis sets are used including diffuse and polarization functions, and that electron correlation corrections are taken into account.…”

Section: Accepted M Manuscriptmentioning

confidence: 99%

Electronic and vibrational polarizabilities of the twenty naturally occurring amino acids

Millefiori

Alparone

Millefiori

et al. 2008

Biophysical Chemistry

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The geometries, relative energies, gas-phase static and dynamic dipole polarizabilities of the two most stable neutral forms and of the zwitterionic form of the twenty naturally occurring amino acids have been obtained by Density Functional and conventional ab initio HatreeFock theories using correlation consistent basis sets. Mean electronic polarizabilities (<α e >s) are encompassed in the 40-160 a.u. range and are little dependent on the amino acid framework conformation, structure and conformation. The relation between <α e > and the number of electrons in the molecule makes to classify the amino acids as one of the most polarizable family of compounds. Calculated <α e > values of the neutral forms linearly relate to the molecular volume and molecular hardness as well as, rather unexpectedly, with the experimental values in water solution, where amino acids are known to be in a zwitterionic form. Vibrational polarizabilities amount to 15-45 a.u.. They come essentially from the lowfrequency angular deformation modes of the -OH and -NH 2 groups.

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Electronic and relaxation contribution to linear molecular polarizability. An analysis of the experimental values

Cited by 134 publications

References 132 publications

Raman Dispersion and Intermolecular Interactions in Unsubstituted Thiophene Oligomers

Raman Dispersion and Intermolecular Interactions in Unsubstituted Thiophene Oligomers

Resonances in low-energy electron scattering from para-benzoquinone

Electronic and vibrational polarizabilities of the twenty naturally occurring amino acids

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