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MP2, Tamm‐Dancoff, and RPA methods based on the generalized HF solution
Author(s) -
Yamaki D.,
Shigeta Y.,
Yamanaka S.,
Nagao H.,
Yamaguchi K.
Publication year - 2000
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 - 10.1002/1097-461x(2000)80:4/5<701::aid-qua19>3.0.co;2-k
Subject(s) - random phase approximation , atomic orbital , excited state , ab initio , spin (aerodynamics) , chemistry , ab initio quantum chemistry methods , molecule , ground state , electronic structure , atomic physics , quantum mechanics , physics , computational chemistry , thermodynamics , electron
Abstract A Hartree–Fock (HF) method dealing with general spin orbitals (GSO) of the form ϕ α α+ϕ β β is called a generalized HF (GHF) method. This method can provide a characteristic electronic state with noncollinear spin configuration. Therefore, it is interesting to apply the method to spin‐frustrated systems. In this study, we have developed ab initio GSO‐based second‐order Møller–Plesset (MP2), Tamm–Dancoff approximation (TDA), and random‐phase approximation (RPA) methods. Further these methods, including GHF, were applied to the H 3 molecule and obtained ground states and excited states of the molecule are discussed. The GSO‐based MP2 method gave a similar energy surface to one of GHF. The GSO‐based TDA and RPA methods found that excitations between the two states correspond to two different GHF solutions. © 2000 John Wiley & Sons, Inc. Int J Quant Chem 80: 701–707, 2000