Convergence to the solution of the eigenvalue problem by perturbative methods
The solution of the Schroedinger equation for molecules leads to a very large-dimension matrix eigenvalue problem. Convergence to the solution of the eigenvalue problem using perturbative methods is investigated. Partitioning technique and perturbation theory are discussed as the basis for large scale diagonalization procedures. In particular multi-reference Rayleigh-Schroedinger perturbation theory is presented in a configuration base scheme, enabling the evaluation of high-order contributions. Problems associated with the convergence of the multi-reference series, as related to the choice of reference space, are discussed and the role of the Pade' approximants for acceleration of convergence is explored. Application of this method to problems of potential energy surfaces and excitation energy calculations are presented. General purpose diagonalization procedures for application to large sparse matrices are also discussed. The relationship of these procedures to the partitioning technique and perturbation theory as well as some examples are presented. The non-symmetric (non-Hermitian) eigenvalue problem, which occurs in several many-body approaches for excited states, is investigated and approaches are proposed for its solution.
- Research Organization:
- Florida Univ., Gainesville, FL (USA)
- OSTI ID:
- 7184054
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
99 GENERAL AND MISCELLANEOUS
990200* -- Mathematics & Computers
CALCULATION METHODS
CONVERGENCE
DATA
DISPERSIONS
EIGENVALUES
ENERGY
ENERGY LEVELS
EXCITED STATES
INFORMATION
MATHEMATICAL MODELS
MIXTURES
NUMERICAL DATA
PERTURBATION THEORY
POTENTIAL ENERGY
RAYLEIGH-SCHROEDINGER FORMULA
SOLUTIONS
THEORETICAL DATA