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Microscopic and macroscopic polarization within a combined quantum mechanics and molecular mechanics model

A polarizable quantum mechanics and molecular mechanics model has been extended to account for the difference between the macroscopic electric field and the actual electric field felt by the solute molecule. This enables the calculation of effective microscopic properties which can be related to macroscopic susceptibilities directly comparable with experimental results. By seperating the discrete local field into two distinct contribution we define two different microscopic properties, the so-called solute and effective properties. The solute properties account for the pure solvent effects, i.e., effects even when the macroscopic electric field is zero, and the effective properties account for both the pure solvent effects and the effect from the induced dipoles in the solvent due to the macroscopic electric field. We present results for the linear and nonlinear polarizabilities of water and acetonitrile both in the gas phase and in the liquid phase. For all the properties we find that the pure solvent effect increases the properties whereas the induced electric field decreases the properties. Furthermore, we present results for the refractive index, third-harmonic generation (THG), and electric field induced second-harmonic generation (EFISH) for liquid water and acetonitrile. We find in general good agreement between the calculated and experimental results for the refractive index and the THG susceptibility. For the EFISH susceptibility, however, the difference between experiment and theory is larger since the orientational effect arising from the static electric field is not accurately described

© Journal of Chemical Physics, 2005, vol. 122, núm. 3, p. 034103

American Institute of Physics

Autor: Jensen, L.
Swart, Marcel
Duijnen, Petrus Theodorus van‏
Data: 2005
Resum: A polarizable quantum mechanics and molecular mechanics model has been extended to account for the difference between the macroscopic electric field and the actual electric field felt by the solute molecule. This enables the calculation of effective microscopic properties which can be related to macroscopic susceptibilities directly comparable with experimental results. By seperating the discrete local field into two distinct contribution we define two different microscopic properties, the so-called solute and effective properties. The solute properties account for the pure solvent effects, i.e., effects even when the macroscopic electric field is zero, and the effective properties account for both the pure solvent effects and the effect from the induced dipoles in the solvent due to the macroscopic electric field. We present results for the linear and nonlinear polarizabilities of water and acetonitrile both in the gas phase and in the liquid phase. For all the properties we find that the pure solvent effect increases the properties whereas the induced electric field decreases the properties. Furthermore, we present results for the refractive index, third-harmonic generation (THG), and electric field induced second-harmonic generation (EFISH) for liquid water and acetonitrile. We find in general good agreement between the calculated and experimental results for the refractive index and the THG susceptibility. For the EFISH susceptibility, however, the difference between experiment and theory is larger since the orientational effect arising from the static electric field is not accurately described
Format: application/pdf
Cita: 005157
ISSN: 0021-9606 (versió paper)
1089-7690 (versió electrònica)
Accés al document: http://hdl.handle.net/10256/8419
Llenguatge: eng
Editor: American Institute of Physics
Col·lecció: Reproducció digital del document publicat a: http://dx.doi.org/10.1063/1.1831271
Articles publicats (D-Q)
És part de: © Journal of Chemical Physics, 2005, vol. 122, núm. 3, p. 034103
Drets: Tots els drets reservats
Matèria: Polarització (Electricitat)
Polarization (Electricity)
Molècules
Molecules
Títol: Microscopic and macroscopic polarization within a combined quantum mechanics and molecular mechanics model
Tipus: info:eu-repo/semantics/article
Repositori: DUGiDocs

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