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Localized orbitals in nonmetallic ring systems
Author(s) -
Reinhardt P.,
Malrieu J.P.,
Povill À.,
Rubio J.
Publication year - 1998
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/(sici)1097-461x(1998)70:1<167::aid-qua14>3.0.co;2-c
Subject(s) - ring (chemistry) , atomic orbital , molecular orbital , chemistry , atomic physics , beryllium , slater type orbital , ionic bonding , molecular physics , computational chemistry , physics , linear combination of atomic orbitals , quantum mechanics , molecule , ion , organic chemistry , electron
Localized molecular Hartree–Fock orbitals have been determined by means of an iterative procedure consisting of orthogonalization and configuration interaction employing single excitations. For ring systems the rotational symmetry has been included explicitly to obtain Wannier‐like orbitals suited for a posteriori correlation calculations using only the most important contributions within a limited region around one reference ring segment. Applications involving different estimates of the correlation energy include as model systems (H 2 ) 2 n +1 , the ionic Li n H n , and a weakly bound beryllium ring as well as the strongly covalent molecule (CH 2 ) 36 forming a closed ring. In all cases, the localized and canonical MP2 results are close, and the localized Epstein–Nesbet second‐order gives a good estimate of more expensive MP4 or CEPA‐0 values. © 1998 John Wiley & Sons, Inc. Int J Quant Chem 70: 167–180, 1998