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Correlated calculations of the electron affinity of HC 2
Author(s) -
Lima Eneida G.,
Canuto Sylvio
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.560340823
Subject(s) - electronic correlation , basis set , electron affinity (data page) , coupled cluster , perturbation theory (quantum mechanics) , gaussian , atomic orbital , chemistry , basis (linear algebra) , electron , adiabatic process , atomic physics , perturbation (astronomy) , physics , statistical physics , quantum mechanics , computational chemistry , density functional theory , mathematics , molecule , geometry
Many‐body perturbation theory, configuration interaction, and coupled‐cluster methods are used with different basis sets to analyze the role of correlation and basis set size effects on the calculated electron affinity of HC 2 . Utilizing an extended basis set consisting of 83 contracted Gaussian‐type orbitals, a CCD calculation gives the value of 3.21 eV for the adiabatic electron affinity of HC 2 in excellent agreement with a previous theoretical result of 3.18 eV obtained by eighth‐order perturbation theory and in good agreement with the experimental result of 2.94 ±0.10 eV Partial inclusion of single excitations, up to the fourth‐order level [ CCD + S‐MBPT (4)] improves the above theoretical result of 3.21 eV to 3.15 eV. The stability of the results with respect to further increase of the basis set size and the amount of correlation corrections is briefly analyzed.