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C..27 PBEXREV: Revised PBE Exchange Functional

Changes the value of the constant R from the original PBEX functional See reference [21] for more details.

\begin{dmath} K= \sum_s 1/2\,E \left( 2\,\rho_{s} \right) ,\end{dmath} where \begin{dmath} E \left( n \right) =-3/4\,{\frac {\sqrt [3]{3}\sqrt [3]{{\pi }^{2}}{n}^ {4/3}F \left( S \right) }{\pi }} ,\end{dmath} \begin{dmath} S=1/12\,{\frac {\chi_{s}{6}^{2/3}}{\sqrt [3]{{\pi }^{2}}}} ,\end{dmath} \begin{dmath} F \left( S \right) =1+R-R \left( 1+{\frac {\mu\,{S}^{2}}{R}} \right) ^{ -1} ,\end{dmath} \begin{dmath} R= 1.245 ,\end{dmath} \begin{dmath} \mu=1/3\,\delta\,{\pi }^{2} \end{dmath} and \begin{dmath} \delta= 0.066725 .\end{dmath} To avoid singularities in the limit $\rho_{\bar{s}}\rightarrow 0$ \begin{dmath} G= 1/2\,E \left( 2\,\rho_{s} \right) .\end{dmath}

molpro@molpro.net
Oct 10, 2007