Molecular structure calculations: A unified quantum mechanical description of electrons and nuclei using explicitly correlated Gaussian functions and the global vector representation

Journal Article · Sat Jul 14 00:00:00 EDT 2012 · Journal of Chemical Physics

DOI:https://doi.org/10.1063/1.4731696· OSTI ID:22098915

Matyus, Edit; Reiher, Markus ^[1]

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1. Laboratory of Physical Chemistry, ETH Zuerich, Wolfgang-Pauli-Str. 10, CH-8093 Zuerich (Switzerland)

We elaborate on the theory for the variational solution of the Schroedinger equation of small atomic and molecular systems without relying on the Born-Oppenheimer paradigm. The all-particle Schroedinger equation is solved in a numerical procedure using the variational principle, Cartesian coordinates, parameterized explicitly correlated Gaussian functions with polynomial prefactors, and the global vector representation. As a result, non-relativistic energy levels and wave functions of few-particle systems can be obtained for various angular momentum, parity, and spin quantum numbers. A stochastic variational optimization of the basis function parameters facilitates the calculation of accurate energies and wave functions for the ground and some excited rotational-(vibrational-)electronic states of H{sub 2}{sup +} and H{sub 2}, three bound states of the positronium molecule, Ps{sub 2}, and the ground and two excited states of the {sup 7}Li atom.

• OSTI ID: 22098915
• Journal Information: Journal of Chemical Physics, Vol. 137, Issue 2; Other Information: (c) 2012 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA); ISSN 0021-9606
• Country of Publication: United States
• Language: English

Related Subjects

74 ATOMIC AND MOLECULAR PHYSICS
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
BORN-OPPENHEIMER APPROXIMATION
BOUND STATE
CARTESIAN COORDINATES
GAUSS FUNCTION
GROUND STATES
HYDROGEN
HYDROGEN IONS 2 PLUS
LITHIUM 7
MOLECULAR STRUCTURE
NUMERICAL ANALYSIS
POLYNOMIALS
POSITRONIUM
QUANTUM MECHANICS
QUANTUM NUMBERS
ROTATIONAL STATES
SCHROEDINGER EQUATION
SPIN
VIBRATIONAL STATES
WAVE FUNCTIONS