Molecular physics and chemistry applications of quantum Monte Carlo
We discuss recent work with the diffusion quantum Monte Carlo (QMC) method in its application to molecular systems. The formal correspondence of the imaginary-time Schroedinger equation to a diffusion equation allows one to calculate quantum mechanical expectation values as Monte Carlo averages over an ensemble of random walks. We report work on atomic and molecular total energies, as well as properties including electron affinities, binding energies, reaction barriers, and moments of the electronic charge distribution. A brief discussion is given on how standard QMC must be modified for calculating properties. Calculated energies and properties are presented for a number of molecular systems, including He, F, F/sup -/, H/sub 2/, N, and N/sub 2/. Recent progress in extending the basic QMC approach to the calculation of ''analytic'' (as opposed to finite-difference) derivatives of the energy is presented, together with an H/sub 2/ potential-energy curve obtained using analytic derivatives.
- Research Organization:
- Materials and Molecular Research Division, Lawrence Berkeley Laboratory, University of California, Berkeley, California 94720
- DOE Contract Number:
- AC03-76SF00098
- OSTI ID:
- 5428358
- Journal Information:
- J. Stat. Phys.; (United States), Journal Name: J. Stat. Phys.; (United States) Vol. 43:3; ISSN JSTPB
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
Molecular & Chemical Physics-- Atomic & Molecular Properties & Theory
640305 -- Atomic
Molecular & Chemical Physics-- Atomic & Molecular Theory-- (-1987)
74 ATOMIC AND MOLECULAR PHYSICS
AFFINITY
ATOMS
BINDING ENERGY
DIFFERENTIAL EQUATIONS
ELEMENTS
ENERGY
ENERGY LEVELS
EQUATIONS
EXPECTATION VALUE
FLUIDS
FLUORINE
GASES
GROUND STATES
HALOGENS
HARTREE-FOCK METHOD
HELIUM
HYDROGEN
MOLECULES
MONTE CARLO METHOD
NITROGEN
NONMETALS
PARTIAL DIFFERENTIAL EQUATIONS
QUADRUPOLE MOMENTS
RARE GASES
SCHROEDINGER EQUATION
USES
WAVE EQUATIONS