TY - JOUR

T1 - Relevance of relativistic exchange-correlation functionals and of finite nuclei in molecular density-functional calculations

AU - Mayer, Markus

AU - Häberlen, Oliver D.

AU - Rösch, Notker

PY - 1996

Y1 - 1996

N2 - Two types of relativistic corrections in molecular electronic structure calculations that are based on the Kohn-Sham approach to density-functional theory have been studied: (1) relativistic corrections to the exchange-correlation functional, both in the local density and in the generalized gradient approximation; (2) a description of the nuclear charge distribution that avoids the Coulomb singularity. The diatomics AuH, AuCl, [Formula Presented], [Formula Presented], and [Formula Presented] were chosen as examples. Although significant effects on the total energy and on core-level energies are found, only the relativistic correction to local-density approximation has a noticeable impact on molecular observables: it induces changes of bond lengths by up to 0.005 Å, of vibrational frequencies by up to 10 [Formula Presented], and of binding energies by up to 0.05 eV. Thus, taken together, the relativistic corrections discussed here are much smaller than those obtained with density-gradient corrections to the exchange-correlation functional. Therefore, the common practice to neglect these relativistic corrections in molecular density-functional calculations is justified, at least for compounds without superheavy elements.

AB - Two types of relativistic corrections in molecular electronic structure calculations that are based on the Kohn-Sham approach to density-functional theory have been studied: (1) relativistic corrections to the exchange-correlation functional, both in the local density and in the generalized gradient approximation; (2) a description of the nuclear charge distribution that avoids the Coulomb singularity. The diatomics AuH, AuCl, [Formula Presented], [Formula Presented], and [Formula Presented] were chosen as examples. Although significant effects on the total energy and on core-level energies are found, only the relativistic correction to local-density approximation has a noticeable impact on molecular observables: it induces changes of bond lengths by up to 0.005 Å, of vibrational frequencies by up to 10 [Formula Presented], and of binding energies by up to 0.05 eV. Thus, taken together, the relativistic corrections discussed here are much smaller than those obtained with density-gradient corrections to the exchange-correlation functional. Therefore, the common practice to neglect these relativistic corrections in molecular density-functional calculations is justified, at least for compounds without superheavy elements.

UR - http://www.scopus.com/inward/record.url?scp=0000770548&partnerID=8YFLogxK

U2 - 10.1103/PhysRevA.54.4775

DO - 10.1103/PhysRevA.54.4775

M3 - Article

AN - SCOPUS:0000770548

SN - 1050-2947

VL - 54

SP - 4775

EP - 4782

JO - Physical Review A

JF - Physical Review A

IS - 6

ER -