Electron affinities of alkali atoms - accuracy at the 5 meV level

Electron affinities of alkali atoms — accuracy at the 5 meV level 

The effect of the model space upon the calculated EA was studied as described above (Sec. 4, Table 3. The model spaces employed are believed 

Correlated electrons in the reference cations and structure of model spaces. 

Electron affinities of the alkali atoms (meV). Fock-space (FS) and intermediate Hamiltonian (IH) compared with experimental [56] (semiempirical [72] for Fr) values.  

Calculated electron affinities are collected and compared with experiment in Table 16. The power of the intermediate Hamiltonian method is demonstrated by the excellent agreement with experiment. The Fock space values start well for Na, but errors increase to 5%, 7% and 9% for the heavier K, Rb and Cs, respectively. IHFSCC values, on the other hand, are all within 5 meV or 1% of experiment. It should be noted that the FSCC function of the anions includes only one determinant in the P space, whereas the IHFSCC P space includes several thousand. The importance of these additional determinants (and of excitations from them to Q) increases with the size of the alkali anion. 

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