X-ray correlated wavefunctions

Thesis/Dissertation · Sat Dec 31 23:00:00 EST 1988

OSTI ID:5223980

Flocco, M M

First- and second order density matrices approximately N-representable by a correlated determinant wavefunction, whose reference state is a single determinant delivering the exact density, are derived. This density-matrix formalism is applied to the calculation of the correlation energy via a formula which includes both a kinetic energy contribution and a potential energy contribution. The single determinant of x-ray orbitals for the beryllium atom is used in a test calculation that yields 65 per cent of the correlation energy in a simple zeroth-order approximation. Extension of the calculations using a Hartree-Fock reference state is carried out for helium and beryllium atoms and for series of ions isoelectronic with them. For beryllium, the accuracy of the Hartree-Fock reference state results is comparable to the x-ray orbitals reference state case. The results for the series of ions are of poorer accuracy as the nuclear charge increases. Also, the empirical formula of Colle and Salvetti for the calculation of the correlation energy is applied to the series of ions isoelectronic with helium and beryllium. The accuracy of the results decreases with the increasing of the nuclear charge in both series.

• Research Organization: City Univ. of New York, NY (United States)
• OSTI ID: 5223980
• Country of Publication: United States
• Language: English

Related Subjects

664100* -- Theory of Electronic Structure of Atoms & Molecules-- (1992-)
74 ATOMIC AND MOLECULAR PHYSICS
ACCURACY
ALKALINE EARTH METALS
ATOMS
BERYLLIUM
CHARGED PARTICLES
CORRELATIONS
DENSITY MATRIX
ELECTROMAGNETIC RADIATION
ELECTRONIC STRUCTURE
ELEMENTS
FLUIDS
FUNCTIONS
GASES
HARTREE-FOCK METHOD
HELIUM
IONIZING RADIATIONS
IONS
ISOELECTRONIC ATOMS
MATRICES
METALS
NONMETALS
RADIATIONS
RARE GASES
WAVE FUNCTIONS
X RADIATION