EXCHANGE ENERGY FROM GAUSSIAN-TYPE BASIS-SETS

Calculations of the Hartree-Fock and local-density approximation excha nge energies for all atoms with Z less-than-or-equal-to 18 using the 6 -311G* Gaussian-type basis set have been carried out. It is found tha t this particular basis set reproduces remarkably well both the Hartre e-Fock and the local-density approximation exchange energies obtained from higher quality Slater-type orbitals. In addition, the Becke corre ction to the local-density approximation exchange energy has been stud ied. The best value of its sole parameter beta, for the 6-311G* basis set, is found to be 0.0051, which differs from its corresponding valu e of 0.0042 obtained with a Slater-type basis set. Results for other s tandard Gaussian basis are also reported.