THE ACCURACY OF THE PSEUDOPOTENTIAL APPROXIMATION - NON-FROZEN-CORE EFFECTS FOR SPECTROSCOPIC CONSTANTS OF ALKALI FLUORIDES XF (X=K, RB, CA)

Citation
T. Leininger et al., THE ACCURACY OF THE PSEUDOPOTENTIAL APPROXIMATION - NON-FROZEN-CORE EFFECTS FOR SPECTROSCOPIC CONSTANTS OF ALKALI FLUORIDES XF (X=K, RB, CA), Chemical physics letters, 255(4-6), 1996, pp. 274-280
Citations number
33
Categorie Soggetti
Physics, Atomic, Molecular & Chemical
Journal title
ISSN journal
00092614
Volume
255
Issue
4-6
Year of publication
1996
Pages
274 - 280
Database
ISI
SICI code
0009-2614(1996)255:4-6<274:TAOTPA>2.0.ZU;2-W
Abstract
The performance of large-core pseudopotentials (ECP), simulating X(+) cotes (X=K, Rb, Cs), and corresponding core-polarization potentials (C PP) is critically anstlyzed in calculations for bond lengths r(e), dis sociation energies D-e, and vibrational frequencies omega(e) of alkali fluorides XF. It is shown that significant errors arise due to both t he ECP modelling of the frozen-core-valence interaction and the CPP tr eatment of non-frozen-core effects. Correcting for these errors, by in troducing small-core ECP and l-dependent CPP, we obtain accuracies of 1 pm for r(e), 0.1 eV for D-e and 5 cm(-1) for omega(e), in coupled cl uster calculations using extended basis sets.