Anharmonic lattice dynamics (LD) and molecular dynamics (MD) calculations have been performed for solid CO2 with two different intermolecular potentials. The IR and Raman spectra of the external phonons have been calculated from the MD simulation in the temperature range 25–150 K. The two potential models are shown to be characterized by a different degree of anharmonicity: very broad bands are obtained with the MOSMD potential, while the PRC-1 potential gives narrower spectral lines, in much better agreement with the experimental data. The anharmonic LD calculations agree with the MD results concerning the lineshape; LD instead predicts much larger positive shifts of the phonon frequencies. Such a discrepancy is attributed to the approximation implicit in the perturbative method utilized in LD.

Molecular dynamics and anharmonic effects in the phonon spectra of solid carbon dioxide / Gianni Cardini;Piero Procacci;Roberto Righini. - In: CHEMICAL PHYSICS. - ISSN 0301-0104. - STAMPA. - 117:(1987), pp. 355-366. [10.1016/0301-0104(87)80188-X]

Molecular dynamics and anharmonic effects in the phonon spectra of solid carbon dioxide

CARDINI, GIANNI;PROCACCI, PIERO;RIGHINI, ROBERTO
1987

Abstract

Anharmonic lattice dynamics (LD) and molecular dynamics (MD) calculations have been performed for solid CO2 with two different intermolecular potentials. The IR and Raman spectra of the external phonons have been calculated from the MD simulation in the temperature range 25–150 K. The two potential models are shown to be characterized by a different degree of anharmonicity: very broad bands are obtained with the MOSMD potential, while the PRC-1 potential gives narrower spectral lines, in much better agreement with the experimental data. The anharmonic LD calculations agree with the MD results concerning the lineshape; LD instead predicts much larger positive shifts of the phonon frequencies. Such a discrepancy is attributed to the approximation implicit in the perturbative method utilized in LD.
1987
117
355
366
Gianni Cardini;Piero Procacci;Roberto Righini
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Utilizza questo identificatore per citare o creare un link a questa risorsa: https://hdl.handle.net/2158/609319
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