An algorithm for nonrelativistic quantummechanical finitenuclearmass variational calculations of nitrogen atom in L = 0, M = 0 states using allelectrons explicitly correlated Gaussian basis functions
An algorithm for quantummechanical nonrelativistic variational calculations of L = 0 and M = 0 states of atoms with an arbitrary number of s electrons and with three p electrons have been implemented and tested in the calculations of the ground {sup 4}S state of the nitrogen atom. The spatial part of the wave function is expanded in terms of allelectrons explicitly correlated Gaussian functions with the appropriate preexponential Cartesian angular factors for states with the L = 0 and M = 0 symmetry. The algorithm includes formulas for calculating the Hamiltonian and overlap matrix elements, as well as formulas for calculating the analytic energy gradient determined with respect to the Gaussian exponential parameters. The gradient is used in the variational optimization of these parameters. The Hamiltonian used in the approach is obtained by rigorously separating the centerofmass motion from the laboratoryframe allparticle Hamiltonian, and thus it explicitly depends on the finite mass of the nucleus. With that, the mass effect on the total groundstate energy is determined.
 Authors:

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 Department of Chemistry, University of Arizona, Tucson, Arizona 85721 (United States)
 (United States)
 Publication Date:
 OSTI Identifier:
 22252907
 Resource Type:
 Journal Article
 Resource Relation:
 Journal Name: Journal of Chemical Physics; Journal Volume: 140; Journal Issue: 17; Other Information: (c) 2014 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; ALGORITHMS; ELECTRONS; GAUSS FUNCTION; GROUND STATES; HAMILTONIANS; MATRIX ELEMENTS; NITROGEN; QUANTUM MECHANICS; WAVE FUNCTIONS