ENCUTGWSOFT: Difference between revisions
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{{TAGDEF|ENCUTGWSOFT|[real] (energy cutoff for response function)|{{TAG|ENCUTGW}}<math>\times 0.8</math> for {{TAG|ALGO}}{{=}}''ACFDT''|{{TAG|ENCUTGW}} else}} | {{TAGDEF|ENCUTGWSOFT|[real] (energy cutoff for response function)|{{TAG|ENCUTGW}}<math>\times 0.8</math> for {{TAG|ALGO}}{{=}}''ACFDT''|{{TAG|ENCUTGW}}else}} | ||
Revision as of 17:24, 15 January 2017
ENCUTGWSOFT = [real] (energy cutoff for response function)
Default: ENCUTGWSOFT = ENCUTGW for ALGO=ACFDT
\begin{tabular} {ll}
Default: \\
{\tt ENCUTGWSOFT}={\tt ENCUTGW}$\times 0.8$ & for {\tt ALGO}=ACFDT \\
{\tt ENCUTGWSOFT}={\tt ENCUTGW} & else \\
\end{tabular}
\vspace{5mm}
The flag allows to truncate the Coulomb kernel slowly between the energy specified by {\tt ENCUTGWSOFT} and {\tt ENCUTGW}. This usually leads to much smoother energy-volume curves in AC-FDT and MP2 calculations. The modified Coulomb kernel is in this case: \[ v_{\bf G} = \frac{4 \pi e^2} {| \bf G|^2} \frac{1}{2} \left( 1 + {\rm cos} \left( \pi \, \frac{ \frac{\hbar^2 |\bf G|^2 }{2 m_e} - {\tt ENCUTGWSOFT}}{ {\tt ENCUTGW - ENCUTGWSOFT}} \right) \right) \qquad \mbox{for} \quad \frac{\hbar^2 |\bf G|^2 }{2 m_e} > {\tt ENCUTGWSOFT} \]
Related Tags and Sections
PRECFOCK, ENCUT, ENCUTGWSOFT, GW calculations