ANTIRES: Difference between revisions
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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. | 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.