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A study of electron affinities using the initiator approach to full configuration interaction quantum Monte Carlo.
- Source :
- Journal of Chemical Physics; 1/14/2011, Vol. 134 Issue 2, p024112, 9p, 2 Charts, 5 Graphs
- Publication Year :
- 2011
-
Abstract
- For the atoms with Z <= 11, energies obtained using the 'initiator' extension to full configuration interaction quantum Monte Carlo (i-FCIQMC) come to within statistical errors of the FCIQMC results. As these FCIQMC values have been shown to converge onto FCI results, the i-FCIQMC method allows similar accuracy to be achieved while significantly reducing the scaling with the size of the Slater determinant space. The i-FCIQMC electron affinities of the Z <= 11 atoms in the aug-cc-pVXZ basis sets are presented here. In every case, values are obtained to well within chemical accuracy [the mean absolute deviation (MAD) from the relativistically corrected experimental values is 0.41 mE<subscript>h</subscript>], and significantly improve on coupled cluster with singles, doubles and perturbative triples [CCSD(T)] results. Since the only remaining source of error is basis set incompleteness, we have investigated using CCSD(T)-F12 contributions to correct the i-FCIQMC results. By doing so, much faster convergence with respect to basis set size may be achieved for both the electron affinities and the FCIQMC ionization potentials presented in a previous paper. With this F12 correction, the MAD can be further reduced to 0.13 mE<subscript>h</subscript> for the electron affinities and 0.31 mE<subscript>h</subscript> for the ionization potentials. [ABSTRACT FROM AUTHOR]
Details
- Language :
- English
- ISSN :
- 00219606
- Volume :
- 134
- Issue :
- 2
- Database :
- Complementary Index
- Journal :
- Journal of Chemical Physics
- Publication Type :
- Academic Journal
- Accession number :
- 57378393
- Full Text :
- https://doi.org/10.1063/1.3525712