ANTIRES: Difference between revisions
(Created page with "{{TAGDEF|ANTIRES|0 {{!}} 1 {{!}} 2}} The flag {{TAG|ANTIRES}} determines whether the Tamm-Dancoff approximation is used or not. The allowed settings are: \begin{tabular}{ll}...") |
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is used or not. The allowed settings are: | is used or not. The allowed settings are: | ||
{{DEF|ANTIRES|0|if {{TAG|LHFCALC}}{{=}}.TRUE.|0|otherwise}} | |||
\begin{tabular}{ll} | \begin{tabular}{ll} | ||
{\tt ANTIRES}=0 & default: Tamm-Dancoff approximation (TDA) \\ | {\tt ANTIRES}=0 & default: Tamm-Dancoff approximation (TDA) \\ | ||
Revision as of 19:33, 13 January 2017
ANTIRES = 0 | 1 | 2
The flag ANTIRES determines whether the Tamm-Dancoff approximation is used or not. The allowed settings are:
| Default: ANTIRES | = 0 | if LHFCALC=.TRUE. |
| = 0 | otherwise |
\begin{tabular}{ll} {\tt ANTIRES}=0 & default: Tamm-Dancoff approximation (TDA) \\ {\tt ANTIRES}=1 & yields exact results at $\omega=0$ at roughly the same cost as TDA \\ {\tt ANTIRES}=2 & beyond Tamm-Dancoff, coupling between positive and negative frequencies \end{tabular}
\noindent VASP uses the procedures outlines in Ref. \cite{Sander15} to include contributions beyond Tamm-Dancoff. Beyond TDA calculations increase the compute time and memory requirements by typically a factor 2.