ISSN:
0020-7608
Keywords:
Computational Chemistry and Molecular Modeling
;
Atomic, Molecular and Optical Physics
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
Basis set “balance” in the expansion of the large and small components of Dirac 4-spinors has proved successful in preventing the blatant “variational failure” that has plagued Dirac-Fock basis set expansion calculations. The criterion of basis set balance, however, was derived from the Dirac equation assuming that the external Coulomb potential V satisfies the condition |V| ≪ c2. Consequently, for a finite value of c, a conventional balanced basis does not necessarily satisfy the boundary condition at the origin, although it may recover the correct nonrelativistic limit as c approaches infinity. This is the case with “balanced” Gaussian basis calculations that employ the point nucleus approximation. We show that this drawback may be removed by forfeiting the point nucleus approximation in favor of a finite nucleus of uniform proton charge distribution: the imposition of the finite nucleus boundary causes the solution to be Gaussian at the origin.
Additional Material:
1 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/qua.560320751
Permalink
