Extensions of the full optimized reaction space model for molecular electronic wavefunctions

Thesis/Dissertation · Sun Jan 01 04:00:00 UTC 1984

OSTI ID:5363067

Lam, M B

A full optimized reaction space (FORS) wavefunction is defined as the optimal configuration interaction wavefunction in a full space of N-electron configurations where all orbitals are optimized. A method is developed for generating configurational basis of such a full reaction space. The results of multi-configuration self-consistent-field (MCSCF) calculations using FORS wavefunctions are discussed for the low-lying electronic states of allene at planar geometries. Two possible augmentations to the FORS model are developed. The first is a semi-empirical correction method, termed the Intra-atomic correlation correction (IACC) model where FORS wave functions are expressed in terms of configurations, generated from localized molecular orbitals, which have the character of atomic states. With the help of these expansions, correlation corrections, available from atoms, are transferred to the molecular wavefunctions. The second augmentation consists of improving the FORS wavefunction by the systematic inclusion of additional configurations involving orbitals outside the valence space. The effectiveness of both approaches is demonstrated by applications to a series of diatomic molecules.

• Research Organization: Iowa State Univ. of Science and Technology, Ames (USA)
• DOE Contract Number: W-7405-ENG-82
• OSTI ID: 5363067
• Country of Publication: United States
• Language: English

Related Subjects

640302* -- Atomic
Molecular & Chemical Physics-- Atomic & Molecular Properties & Theory
74 ATOMIC AND MOLECULAR PHYSICS
ALLENE
DIENES
ELECTRONIC STRUCTURE
FUNCTIONS
HYDROCARBONS
MATHEMATICAL MODELS
MOLECULAR MODELS
MOLECULAR ORBITAL METHOD
ORGANIC COMPOUNDS
POLYENES
SELF-CONSISTENT FIELD
WAVE FUNCTIONS