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Difference between revisions of "ANTIRES"

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is used or not. The allowed settings are:
 
is used or not. The allowed settings are:
  
{{DEF|ANTIRES|0|default: Tamm-Dancoff  approximation (TDA)|1|yields exact results at <math>\\omega=0</math> at roughly the same cost  as TDA|2|beyond Tamm-Dancoff, coupling between positive and negative frequencies}}
+
{{DEF|ANTIRES|0|default: Tamm-Dancoff  approximation (TDA)|1|yields exact results at <math>\omega=0</math> at roughly the same cost  as TDA|2|beyond Tamm-Dancoff, coupling between positive and negative frequencies}}
  
 
\begin{tabular}{ll}
 
\begin{tabular}{ll}

Revision as of 20:14, 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 default: Tamm-Dancoff approximation (TDA)
= 1 yields exact results at at roughly the same cost as TDA
= 2 beyond Tamm-Dancoff, coupling between positive and negative frequencies

\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.



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