Approximate Quantum Dynamics using Ab Initio Classical Separable Potentials: Spectroscopic Applications.
Algorithms for quantum molecular dynamics simulations that directly use ab initio methods have many potential applications. In this article, the ab initio classical separable potentials (AICSP) method is proposed as the basis for approximate algorithms of this type. The AICSP method assumes separability of the total time-dependent wave function of the nuclei and employs mean-field potentials that govern the dynamics of each degree of freedom. In the proposed approach, the mean-field potentials are determined by classical ab initio molecular dynamics simulations. The nuclear wave function can thus be propagated in time using the effective potentials generated "on the fly". As a test of the method for realistic systems, calculations of the stationary anharmonic frequencies of hydrogen stretching modes were carried out for several polyatomic systems, including three amino acids and the guanine-cytosine pair of nucleobases. Good agreement with experiments was found. The method scales very favorably with the number of vibrational modes and should be applicable for very large molecules, e.g., peptides. The method should also be applicable for properties such as vibrational line widths and line shapes. Work in these directions is underway.
Institute of Chemistry and the Fritz Haber Center for Molecular Dynamics, The Hebrew University , Jerusalem 9190401, Israel.
Barak
http://orcid.org/0000-0002-0014-515X
B
Hirshberg
Institute of Chemistry and the Fritz Haber Center for Molecular Dynamics, The Hebrew University , Jerusalem 9190401, Israel.
Lior
L
Sagiv
Institute of Chemistry and the Fritz Haber Center for Molecular Dynamics, The Hebrew University , Jerusalem 9190401, Israel.|Department of Chemistry, University of California , Irvine, California 92697, United States.
R Benny
RB
Gerber