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The IR spectrum of supercritical water: Combined molecular dynamics/quantum mechanics strategy and force field for cluster sampling
Author(s) -
Bordat P.,
Bégué D.,
Brown R.,
Marbeuf A.,
Cardy H.,
Baraille I.
Publication year - 2011
Publication title -
international journal of quantum chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.484
H-Index - 105
eISSN - 1097-461X
pISSN - 0020-7608
DOI - 10.1002/qua.23286
Subject(s) - supercritical fluid , molecular dynamics , force field (fiction) , intermolecular force , trimer , spectral line , water cluster , hydrogen bond , quantum , chemistry , potential energy surface , chemical physics , water model , cluster (spacecraft) , computational chemistry , molecule , physics , quantum mechanics , dimer , organic chemistry , computer science , programming language
Supercritical water was analyzed recently as a gas of small clusters of waters linked to each other by intermolecular hydrogen‐bonds, but unexpected “linear” conformations of clusters are required to reproduce the infra‐red (IR) spectra of the supercritical state. Aiming at a better understanding of clusters in supercritical water, this work presents a strategy combining classical molecular dynamics to explore the potential energy landscape of water clusters with quantum mechanical calculation of their IR spectra. For this purpose, we have developed an accurate and flexible force field of water based on the TIP5P 5‐site model. Water dimers and trimers obtained with this improved force field compare well with the quantum mechanically optimized clusters. Exploration by simulated annealing of the potential energy surface of the classical force field reveals a new trimer conformation whose IR response determined from quantum calculations could play a role in the IR spectra of supercritical water. © 2011 Wiley Periodicals, Inc. Int J Quantum Chem, 2011