Big Chemical Encyclopedia

Chemical substances, components, reactions, process design ...

Articles Figures Tables About

Linear operator annihilation method

This difficulty is overcome with the aid of a projection operator by projecting out from the Slater determinant the component with the desired multiplicity 25+1, annihilating all other contaminating components. This can be done either after an already performed calculation (spin projection after variation, UHF with annihilation), or, as Lowdin has pointed out, one would expect a more negative total energy if the variation is performed with an already spin-projected Slater determinant [spin projection before variation, spin-projected extended Hartree-Fock (EHF) method]. The reason is that a spin-projected Slater determinant is a given linear combination of different Slater determinants. The variation in the expectation value of the Hamiltonian formed with a spin-projected Sater determinant thus provides equations (EHF equations), whose solutions represent the solution of this particular multiconfigura-tional SCF problem. [Pg.29]


See other pages where Linear operator annihilation method is mentioned: [Pg.94]    [Pg.41]    [Pg.235]    [Pg.411]    [Pg.299]    [Pg.577]    [Pg.286]    [Pg.538]   
See also in sourсe #XX -- [ Pg.50 , Pg.51 , Pg.52 , Pg.53 , Pg.54 ]




SEARCH



Annihilate

Annihilation

Annihilation method

Linear methods

Linear operations

Linear operator

Linearized methods

Operating Methods

Operator annihilation

© 2024 chempedia.info