Direct calculation of the Hartree-Fock density matrix

Thesis/Dissertation · Tue Jan 01 00:00:00 EST 1985

OSTI ID:5611351

Waggoner, C A

Equations are generated for a direct (non-SCF) calculation of the Hartree-Fock density matrix. The existing ab initio program MOLECI is modified for the direct calculation of the density matrix (DCDM). Two problem formulations are investigated. Density matrices are calculated that are constrained only to the proper total population. This constraint is taken into account using the method of Lagrange undetermined multipliers. The system of first partial derivatives of the Lagrangian functions are solved by a Gauss-Jordan technique. Calculations of this type are done for the hydrogen fluoride, water, methane, boron hydride, and hydrogen molecules. DCDM calculations are also completed for density matrices constrained to both the proper total population and idempotency. In this formulation, the constraints are taken into account as penalty functions and the solution is obtained using a nonlinear optimizer. Idempotent density matrices are calculated for the hydrogen molecule as well as for hydrogen fluoride and boron hydride. Criteria are proposed for judging the quality of DCDM solution obtained for hydrogen molecule calculations. The global optimum solution for the hydrogen molecule was not found as judged by these proposed criteria.

• Research Organization: Mississippi State Univ., State College (USA)
• OSTI ID: 5611351
• Resource Relation: Other Information: Thesis (Ph. D.)
• Country of Publication: United States
• Language: English

Related Subjects

74 ATOMIC AND MOLECULAR PHYSICS
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
HARTREE-FOCK METHOD
DENSITY MATRIX
BORON HYDRIDES
COMPUTER CALCULATIONS
COMPUTER CODES
HYDROFLUORIC ACID
HYDROGEN
LAGRANGIAN FUNCTION
METHANE
MOLECULES
WATER
ALKANES
BORON COMPOUNDS
ELEMENTS
FUNCTIONS
HYDRIDES
HYDROCARBONS
HYDROGEN COMPOUNDS
INORGANIC ACIDS
MATRICES
NONMETALS
ORGANIC COMPOUNDS
OXYGEN COMPOUNDS
640305* - Atomic
Molecular & Chemical Physics- Atomic & Molecular Theory- (-1987)
657002 - Theoretical & Mathematical Physics- Classical & Quantum Mechanics