Next: C..7 B88: Becke88 Exchange Up: C. Density functional descriptions Previous: C..5 B88CMASK:


C..6 B88C: Becke88 Correlation Functional

Correlation functional depending on B86MGC exchange functional with empirical atomic parameters, $t$ and $u$. The exchange functional that is used in conjunction with B88C should replace B88MGC here. See reference [11] for more details.

\begin{dmath}
K=
- 0.8\,\rho_{\alpha}\rho_{\beta}{q}^{2} \left( 1-{\frac {\ln \l...
...{4} \left( 1-2\,{\frac {\ln \left( 1+1/2\,z
\right) }{z}} \right)
,\end{dmath} where \begin{dmath}
q=t \left( x+y \right)
,\end{dmath} \begin{dmath}
x= 0.5\, \left( c\sqrt [3]{\rho_{\alpha}}+{\frac {\beta\, \left(
...
...,
\left( \chi_{\alpha} \right) ^{2} \right) ^{4/5}}} \right) ^{-1}
,\end{dmath} \begin{dmath}
y= 0.5\, \left( c\sqrt [3]{\rho_{\beta}}+{\frac {\beta\, \left(
\...
...\,
\left( \chi_{\beta} \right) ^{2} \right) ^{4/5}}} \right) ^{-1}
,\end{dmath} \begin{dmath}
t= 0.63
,\end{dmath} \begin{dmath}
z=2\,ur
,\end{dmath} \begin{dmath}
r= 0.5\,\rho_{s} \left( c \left( \rho_{s} \right) ^{4/3}+{\frac {\...
...mbda\, \left( \chi_{s} \right) ^{2} \right) ^{4/5}}}
\right) ^{-1}
,\end{dmath} \begin{dmath}
u= 0.96
,\end{dmath} \begin{dmath}
d=\tau_{s}-1/4\,{\frac {\sigma_{ss}}{\rho_{s}}}
,\end{dmath} \begin{dmath}
c=3/8\,\sqrt [3]{3}{4}^{2/3}\sqrt [3]{{\pi }^{-1}}
,\end{dmath} \begin{dmath}
\beta= 0.00375
\end{dmath} and \begin{dmath}
\lambda= 0.007
.\end{dmath} To avoid singularities in the limit $\rho_{\bar{s}}\rightarrow 0$ \begin{dmath}
G=
- 0.01\,\rho_{s}d{z}^{4} \left( 1-2\,{\frac {\ln \left( 1+1/2\,z
\right) }{z}} \right)
.\end{dmath}


molpro@molpro.net
Oct 10, 2007