PSEUDOPOTENTIALS FROM ORBITAL-DEPENDENT EXCHANGE-CORRELATION FUNCTIONALS

Norm-conserving pseudopotentials are generated on the basis of the opt imized potential method (OPM), combining the exact exchange with two d ifferent correlation functionals, i.e., the orbital-dependent form of Colle and Salvetti (CS) [Theor. Chim. Acta 37, 329 (1975)] and the loc al density approximation (LDA). Application of both types of OPM pseud opotentials to a number of diatomic molecules leads to substantially d ifferent predictions for spectroscopic constants, thus indicating the importance of a suitable choice for the correlation functional to be u sed in the OPM context. Moreover, while the CS values are closet to th e experimental data, our results nevertheless indicate that a really a dequate correlation functional for use with the exact exchange is not yet available. In any case, both variants of the OPM-based pseudopoten tials show an improved transferability compared with standard LDA pseu dopotentials. [S1050-2947(98)03811-6].