Article

Ab initio molecular dynamics: Propagating the density matrix with gaussian orbitals. IV. Formal analysis of the deviations from born-oppenheimer dynamics

  1. Srinivasan S. Iyengar1,
  2. H. Bernhard Schlegel2,
  3. Gregory A. Voth1,*,
  4. John M. Millam2,
  5. Gustavo E. Scuseria3,
  6. Michael J. Frisch4

Article first published online: 8 MAR 2010

DOI: 10.1560/GLW2-8NVQ-4N6T-6C92

Issue

Israel Journal of Chemistry

Israel Journal of Chemistry

Special Issue: Computational Chemistry of Quantum Mechanical Processes

Volume 42, Issue 2-3, pages 191–202, April 2003

Additional Information

How to Cite

Iyengar, S. S., Schlegel, H. B., Voth, G. A., Millam, J. M., Scuseria, G. E. and Frisch, M. J. (2002), Ab initio molecular dynamics: Propagating the density matrix with gaussian orbitals. IV. Formal analysis of the deviations from born-oppenheimer dynamics. Isr. J. Chem., 42: 191–202. doi: 10.1560/GLW2-8NVQ-4N6T-6C92

Author Information

  1. 1

    Department of Chemistry and Henry Eyring Center for Theoretical Chemistry, 315 S. 1400 E. Rm. 2020, University of Utah, Salt Lake City, Utah 84112-0850, USA

  2. 2

    Department of Chemistry, Wayne State University, Detroit, Michigan 48202-3489, USA

  3. 3

    Department of Chemistry and Center for Nanoscale Science and Technology, Rice University, Houston, Texas 77005-1892, USA

  4. 4

    Gaussian, Inc., 140 Washington Ave., North Haven, Connecticut 06473-1712, USA

*Department of Chemistry and Henry Eyring Center for Theoretical Chemistry, 315 S. 1400 E. Rm. 2020, University of Utah, Salt Lake City, Utah 84112-0850, USA

Publication History

  1. Issue published online: 8 MAR 2010
  2. Article first published online: 8 MAR 2010
  3. Manuscript Revised: 15 JAN 2003
  4. Manuscript Received: 18 OCT 2002

Funded by

  • Office of Naval Research (GAV)
  • Natural Science Foundation. Grant Number: (CHE-9982156 and CHE-0131157)

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Abstract

In the context of the recently developed Atom-centered Density Matrix Propagation (ADMP) approach to ab initio molecular dynamics, a formal analysis of the deviations from the Born—Oppenheimer surface is conducted. These deviations depend on the fictitious mass and on the magnitude of the commutator of the Fock and density matrices. These quantities are found to be closely interrelated and the choice of the fictitious mass provides a lower bound on the deviations from the Born—Oppenheimer surface. The relations are illustrated with an example calculation for the Cl−(H2O)25 cluster. We also show that there exists a direct one-to-one correspondence between approximate Born—Oppenheimer dynamics, where SCF convergence is restricted by a chosen threshold value for the commutator of the Fock and density matrices, and extended Lagrangian dynamics performed using a finite value for the fictitious mass. The analysis is extended to the nuclear forces used in the ADMP approximation. The forces are shown to be more general than those standardly used in Born—Oppenheimer dynamics, with the addition terms in the nuclear forces depending on the commutator mentioned above.

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