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Full configuration interaction for the benzyl radical
Author(s) -
Kuprievich V. A.,
Kruglyak Yuri A.,
Mozdor E. V.
Publication year - 1970
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.560040107
Subject(s) - excited state , configuration interaction , wave function , hamiltonian (control theory) , chemistry , atomic orbital , hyperfine structure , electronic correlation , computational chemistry , ground state , computation , atomic physics , open shell , molecular physics , physics , quantum mechanics , molecule , mathematics , algorithm , electron , mathematical optimization
The electronic structure of the benzyl radical in its ground state has been computed using a model Hamiltonian due to Pariser–Parr with full configuration interaction as well as with different truncated configurational sets built on SCF open‐shell orbitals. The correlation energy corresponding to this model was found to be equal to –0.929722 eV. With the singly excited configurations only 18% of this energy is taken into account. By extending the basis to include the doubly excited configurations one can account for 94% of the correlation energy. An analysis of the accuracy of the proton hyperfine splitting calculation caused by inaccurate computation of the wave function is given. If only singly and even doubly excited configurations are taken into account one cannot hope to obtain splittings with an accuracy of more than 0.5 g . Inclusion of triply excited configurations lowers this error by one order. In addition, the use of the simple McConnell relation may lead to an error in splitting calculations of no less than 1.5 g .