Norm-conserving pseudopotentials are generated on the basis of the optimized potential method ͑OPM͒, combining the exact exchange with two different correlation functionals, i.e., the orbital-dependent form of Colle and Salvetti ͑CS͒ ͓Theor. Chim. Acta 37, 329 ͑1975͔͒ and the local density approximation ͑LDA͒. Application of both types of OPM pseudopotentials to a number of diatomic molecules leads to substantially different predictions for spectroscopic constants, thus indicating the

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... of a suitable choice for the correlation functional to be used in the OPM context. Moreover, while the CS values are closer to the experimental data, our results nevertheless indicate that a really adequate correlation functional for use with the exact exchange is not yet available. In any case, both variants of the OPM-based pseudopotentials show an improved transferability compared with standard LDA pseudopotentials.