Article ID Journal Published Year Pages File Type
9575417 Chemical Physics 2005 6 Pages PDF
Abstract
Ionization potentials of orbitals in the three shells above the cation closed-shell structure (17 IPs per atom) are calculated for the alkali atoms Rb, Cs, Fr and element 119. The Dirac-Coulomb-Breit Hamiltonian is used as framework, and correlation is included by the multireference Fock-space coupled cluster method with single and double excitations. The basis includes 36s32p24d22f10g7h6i Gaussian-type orbitals. Comparison with the 45 experimentally known IPs shows excellent agreement, with an average absolute error of 11 cm−1 (1.4 meV) or 0.10% and maximum error of 81 cm−1 (10 meV) or 0.25%. The largest errors occur in the ground state IPs. Correcting for the Lamb shifts improves the s orbital binding energies, reducing the maximum error to 60 cm−1 (7.4 meV) or 0.19%. The remaining error is attributed to the truncation of the coupled cluster expansion and, to lesser extent, to small deficiencies in the basis.
Related Topics
Physical Sciences and Engineering Chemistry Physical and Theoretical Chemistry
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