Exchange potential gradient-corrected

Calculations for rutile and anatase were performed using both LDA level of DFT and the gradient corrected form of the exchange-correlation potential (GGA). The GGA approach is implemented self-consistently as described in 18 and not as a post-SCF correction. 

J.A. White and D.M. Bird, Implementation of gradient corrected exchange-correlation potentials in Car-... 

Chermette, H., Lembarki, A., Razafinjanahary, H., Rogemond, 1998, Gradient-Corrected Exchange Potential Functional With the Correct Asymptotic Behavior , Adv. Quant. Chem., 33, 105. 

Lembarki, A., F. Regemont, and H. Chermette. 1995. Gradient-corrected exchange potential with the correct asymptotic behavior and the corresponding exchange-energy functional obtained from virial theorem. Phys. Rev. A 52, 3704. 

The wave functions are expended in a plane wave basis set, and the effective potential of ions is described by ultrasoft pseudo potential. The generalized gradient approximation (GGA)-PW91, and local gradient-corrected exchange-correlation functional (LDA)-CAPZ are used for the exchange-correlation functional. 

Gradient-corrected Exchange Potential Functional with the correct asymptotic behaviour... 

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