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Difference between revisions of "ANTIRES"

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{{TAGDEF|ANTIRES|0 {{!}} 1 {{!}} 2|0}}
 
{{TAGDEF|ANTIRES|0 {{!}} 1 {{!}} 2|0}}
  
The flag {{TAG|ANTIRES}} determines whether the Tamm-Dancoff approximation
+
Description: The flag {{TAG|ANTIRES}} determines whether the Tamm-Dancoff approximation
is used or not. The allowed settings are:
+
is used or not.  
 +
----
 +
*{{TAG|ANTIRES}}=0 Tamm-Dancoff  approximation (TDA)
 +
*{{TAG|ANTIRES}}=1 yields exact results at  ω{{=}}1  at roughly the same cost  as TDA
 +
*{{TAG|ANTIRES}}=2 beyond Tamm-Dancoff, coupling between positive and negative frequencies
  
 
{{DEF|ANTIRES|0|default: Tamm-Dancoff  approximation (TDA)|1|yields exact results at  ω{{=}}1  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  ω{{=}}1  at roughly the same cost  as TDA|2|beyond Tamm-Dancoff, coupling between positive and negative frequencies}}

Revision as of 11:16, 14 January 2017

ANTIRES = 0 | 1 | 2
Default: ANTIRES = 0 

Description: The flag ANTIRES determines whether the Tamm-Dancoff approximation is used or not.


  • ANTIRES=0 Tamm-Dancoff approximation (TDA)
  • ANTIRES=1 yields exact results at ω=1 at roughly the same cost as TDA
  • ANTIRES=2 beyond Tamm-Dancoff, coupling between positive and negative frequencies
Default: ANTIRES = 0 default: Tamm-Dancoff approximation (TDA)
= 1 yields exact results at ω=1 at roughly the same cost as TDA
= 2 beyond Tamm-Dancoff, coupling between positive and negative frequencies


VASP uses the procedures outlined in Ref. \cite{Sander15} to include contributions beyond Tamm-Dancoff. Beyond TDA calculations increase the computational time and memory requirements by typically a factor of 2.



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