In the current opinion, the inclusion of polarization response in classical computer simulations is considered as one of the most important and urgent improvements to be implemented in modern empirical potential models. In this work we focus on the capability of polarizable models, based on the pairwise Coulomb interactions, to model systems where strong electric fields enter into play. As shown by Masia, Probst, and Rey (MPR) [in J. Chem. Phys. 121, 7362 (2004)], when a molecule interacts with point charges, polarizable models show underpolarization with respect to ab initio methods. We prove that this underpolarization, clearly related to nonlinear polarization effects, cannot be simply ascribed to the lack of hyperpolarization in the polarizable models, as suggested by MPR. Analysis of the electron-density rearrangement induced on a water molecule by a point charge reveals a twofold level of polarization response. One level involves intramolecular charge transfer on the whole molecular volume, with the related polarization exhibiting a seemingly linear behavior with the external electric field. The other nonlinear polarization level occurs only at strong electric fields and is found to be strictly correlated to the quantum-mechanical nature of the water molecule. The latter type of polarization has a local character, being limited to the space region of the water lone pairs.
Behavior of polarizable models in presence of strong electric fields. I. Origin of nonlinear effects in water point-charge systems / Chelli, Riccardo; Barducci, Alessandro; Bellucci, Luca; Schettino, Vincenzo; Procacci, Piero. - In: THE JOURNAL OF CHEMICAL PHYSICS. - ISSN 0021-9606. - STAMPA. - 123:(2005), pp. 194109-1-194109-8. [10.1063/1.2110107]
Behavior of polarizable models in presence of strong electric fields. I. Origin of nonlinear effects in water point-charge systems
CHELLI, RICCARDO;SCHETTINO, VINCENZO;PROCACCI, PIERO
2005
Abstract
In the current opinion, the inclusion of polarization response in classical computer simulations is considered as one of the most important and urgent improvements to be implemented in modern empirical potential models. In this work we focus on the capability of polarizable models, based on the pairwise Coulomb interactions, to model systems where strong electric fields enter into play. As shown by Masia, Probst, and Rey (MPR) [in J. Chem. Phys. 121, 7362 (2004)], when a molecule interacts with point charges, polarizable models show underpolarization with respect to ab initio methods. We prove that this underpolarization, clearly related to nonlinear polarization effects, cannot be simply ascribed to the lack of hyperpolarization in the polarizable models, as suggested by MPR. Analysis of the electron-density rearrangement induced on a water molecule by a point charge reveals a twofold level of polarization response. One level involves intramolecular charge transfer on the whole molecular volume, with the related polarization exhibiting a seemingly linear behavior with the external electric field. The other nonlinear polarization level occurs only at strong electric fields and is found to be strictly correlated to the quantum-mechanical nature of the water molecule. The latter type of polarization has a local character, being limited to the space region of the water lone pairs.File | Dimensione | Formato | |
---|---|---|---|
J.Chem.Phys.-y05_v123_p194109.pdf
Accesso chiuso
Descrizione: Articolo principale
Tipologia:
Pdf editoriale (Version of record)
Licenza:
Tutti i diritti riservati
Dimensione
129.68 kB
Formato
Adobe PDF
|
129.68 kB | Adobe PDF | Richiedi una copia |
I documenti in FLORE sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.