RELATIVISTIC AND ELECTRON-CORRELATION CONTRIBUTIONS IN ATOMIC AND MOLECULAR-PROPERTIES - BENCHMARK CALCULATIONS ON AU AND AU2

Multi-electron adjusted relativistic and nonrelativistic pseudopotential QCISD(T) calculations on Au and Au2 using rather large basis sets have been carried out in order to obtain accurate values for relativistic changes in atomic and molecular properties. The relativistically derived results are in good agreement with experimental values. At the correlated level, the relativistic changes are predicted as follows (a minus sign denotes a relativistic increase): Au ionization potential -2.01 eV, Au electron affinity -1.07 eV, Au2 bond distance 0.25 angstrom, Au2 force constant -1.0 mdyn/angstrom, Au2 dissociation energy -86 kJ/mol.