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Density and density matrix from optimized linearly independent product basis functions for Be
Author(s) -
Morrison Robert C.
Publication year - 1988
Publication title -
international journal of quantum chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.484
H-Index - 105
eISSN - 1097-461X
pISSN - 0020-7608
DOI - 10.1002/qua.560340809
Subject(s) - basis set , wave function , atomic orbital , basis (linear algebra) , density matrix , eigenvalues and eigenvectors , matrix (chemical analysis) , basis function , configuration interaction , atomic physics , linear combination of atomic orbitals , slater type orbital , sto ng basis sets , atom (system on chip) , quantum mechanics , physics , chemistry , density functional theory , excited state , mathematics , electron , geometry , quantum , computer science , embedded system , chromatography
The density matrix was computed from the density using basis orbitals which form linearly independent products ( LIP ). Calculations were performed on the Be atom using LIP bases containing several of the natural spin orbitals from an accurate nonrelativistic 650‐term configuration interaction ( CI ) wavefunction. Calculations were also performed using a basis set of 6 s ‐type orbitals optimized so that the lowest eigenvalue, d 1 , of the overlap matrix of products is maximized and the energy of a small CI wavefunction is minimized. The value of d 1 in the optimized basis is 1 × 10 −7 . The density and the potential energy obtained from the 650‐term CI wavefunction were accurately reproduced by the density matrix expressed in the optimized LIP basis, but the kinetic energy was somewhat less accurate.