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Title: An efficient and stable hybrid extended Lagrangian/self-consistent field scheme for solving classical mutual induction

We have adapted a hybrid extended Lagrangian self-consistent field (EL/SCF) approach, developed for time reversible Born Oppenheimer molecular dynamics for quantum electronic degrees of freedom, to the problem of classical polarization. In this context, the initial guess for the mutual induction calculation is treated by auxiliary induced dipole variables evolved via a time-reversible velocity Verlet scheme. However, we find numerical instability, which is manifested as an accumulation in the auxiliary velocity variables, that in turn results in an unacceptable increase in the number of SCF cycles to meet even loose convergence tolerances for the real induced dipoles over the course of a 1 ns trajectory of the AMOEBA14 water model. By diagnosing the numerical instability as a problem of resonances that corrupt the dynamics, we introduce a simple thermostating scheme, illustrated using Berendsen weak coupling and Nose-Hoover chain thermostats, applied to the auxiliary dipole velocities. We find that the inertial EL/SCF (iEL/SCF) method provides superior energy conservation with less stringent convergence thresholds and a correspondingly small number of SCF cycles, to reproduce all properties of the polarization model in the NVT and NVE ensembles accurately. Our iEL/SCF approach is a clear improvement over standard SCF approaches to classical mutual inductionmore » calculations and would be worth investigating for application to ab initio molecular dynamics as well.« less
Authors:
 [1] ;  [2] ;  [1] ;  [3] ;  [3] ;  [3]
  1. Department of Chemical and Biomolecular Engineering, University of California, Berkeley, California 94720 (United States)
  2. Department of Chemistry, University of California, Berkeley, California 94720 (United States)
  3. (United States)
Publication Date:
OSTI Identifier:
22493189
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Chemical Physics; Journal Volume: 143; Journal Issue: 17; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; 37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; 97 MATHEMATICAL METHODS AND COMPUTING; BORN-OPPENHEIMER APPROXIMATION; CONVERGENCE; DEGREES OF FREEDOM; DIPOLES; ENERGY CONSERVATION; LAGRANGIAN FUNCTION; MOLECULAR DYNAMICS METHOD; POLARIZATION; QUANTUM ELECTRONICS; SELF-CONSISTENT FIELD; THERMOSTATS; WATER