An Exchange-Correlation Potential With Built in Discontinuity and Correct Long Range Behavior

摘要

The Casida and Salahub asymptotic correction approach (J. Chem. Phys. 113, 8918 (2000)), which shifts the exchange-correlation potential of a continuum exchange-correlation energy functional to describe the energetically important region and splices it to a potential with the correct long range behavior for the asymptotic region, is analyzed in the context of the derivative discontinuity of the exact exchange-correlation energy functional, to simplify the calculation of the constant shift through a second-order one-body perturbation approach, that can be incorporated to the self-consistent field cycle, with a very small additional computational effort. The results thus obtained are quite similar to those of the original method. The advantage is that the present approach is self-contained and it does not require an ionization potential as an external parameter from a separate calculation.