Abstract
We propose two simple, first-principles generalized gradient corrections for exchange, which are exact for the one- and two-electron oscillator and for the weakly perturbed electron gas in second order of the gradient and which are very close to Becke’s empirical correction. Also, the procedure is given for fulfilling additional exact constraints. The result is tested for the exchange energy of atoms and some exactly solved one- and two-electron problems in the external potentials -Z/r and 1/2 for a wide range of the parameters Z and ω. © 1996 The American Physical Society.
- Received 2 October 1995
DOI:https://doi.org/10.1103/PhysRevA.53.3143
©1996 American Physical Society