Accession Number:

AD0600166

Title:

THE DIRECT DETERMINATION OF NATURAL ORBITALS AND NATURAL EXPANSION COEFFICIENTS OF MANY ELECTRON WAVE FUNCTIONS. I. NATURAL ORBITALS IN THE GEMINAL PRODUCT APPROXIMATION.

Descriptive Note:

Scientific rept. no. 7,

Corporate Author:

UPPSALA UNIV (SWEDEN)

Personal Author(s):

• Kutzelnigg,Werner

Report Date:

1964-01-01

Pagination or Media Count:

23.0

Abstract:

The approximation of a many particle wave function as an antisymmetrized product of strongly orthogonal geminals APSG geminal means two electron function is analized in terms of its natural expansion. APSG wave functions have very simple and interesting properties. The generating spin geminals GSG are automatically natural spin geminals NSG of the system with occupation number 1 in the Lowdin normalization 1 is the upper bound for the eigenvalues of the 2 particle density matrix for wave functions of this type. The natural spin orbitals NSO of the GSG are automatically NSO of the total wave function and of all the NSG. A generalized paired orbital function is defined in terms of its natural expansion. It contains the APSG type as well as the BardeenCooper-Schrieffer BCS-functions as special cases. Integrodifferential equations determining the NSO and their expansion coefficients for an APSG function are derived for the special case of a singlet state by minimizing the total electronic energy. An iterative resolution procedure is proposed. Author

Descriptors:

• (*ATOMIC ORBITALS
• FIELD THEORY)
• (*QUANTUM THEORY
• ATOMIC ORBITALS)
• ELECTRONS
• SPECIAL FUNCTIONS (MATHEMATICAL)
• INTEGRAL EQUATIONS
• PARTIAL DIFFERENTIAL EQUATIONS
• NUMERICAL ANALYSIS
• ITERATIONS

Subject Categories:

Distribution Statement:

APPROVED FOR PUBLIC RELEASE