ENCUTGWSOFT: Difference between revisions
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specified by {{TAG|ENCUTGWSOFT}} and {{TAG|ENCUTGW}}. | specified by {{TAG|ENCUTGWSOFT}} and {{TAG|ENCUTGW}}. | ||
---- | ---- | ||
This usually leads to much smoother energy-volume curves in | This usually leads to much smoother energy-volume curves in {{TAG|ACFDT calculations}} and {{TAG|MP2 calculations}}. | ||
The modified Coulomb kernel is in this case: | The modified Coulomb kernel is in this case: | ||
<math>v_{\bold{G}} = \frac{4 \pi e^2} {| \bold{G}|^2} \frac{1}{2} \left( 1 + \mathbf{cos} \left( \pi \, \frac{ \frac{\hbar^{2} |\bold{G}|^2 }{2 m_e} - \mathbf{ENCUTGWSOFT}}{ \mathbf{ENCUTGW} - \mathbf{ENCUTGWSOFT}} \right) \right) | <math>v_{\bold{G}} = \frac{4 \pi e^2} {| \bold{G}|^2} \frac{1}{2} \left( 1 + \mathbf{cos} \left( \pi \, \frac{ \frac{\hbar^{2} |\bold{G}|^2 }{2 m_e} - \mathbf{ENCUTGWSOFT}}{ \mathbf{ENCUTGW} - \mathbf{ENCUTGWSOFT}} \right) \right) | ||
Revision as of 10:54, 18 January 2017
ENCUTGWSOFT = [real] (energy cutoff for response function)
| Default: ENCUTGWSOFT | = ENCUTGW[math]\displaystyle{ \times 0.8 }[/math] | for ALGO=ACFDT |
| = ENCUTGW | else |
Descprition: The flag allows to truncate the Coulomb kernel slowly between the energy specified by ENCUTGWSOFT and ENCUTGW.
This usually leads to much smoother energy-volume curves in ACFDT calculations and MP2 calculations. The modified Coulomb kernel is in this case: [math]\displaystyle{ v_{\bold{G}} = \frac{4 \pi e^2} {| \bold{G}|^2} \frac{1}{2} \left( 1 + \mathbf{cos} \left( \pi \, \frac{ \frac{\hbar^{2} |\bold{G}|^2 }{2 m_e} - \mathbf{ENCUTGWSOFT}}{ \mathbf{ENCUTGW} - \mathbf{ENCUTGWSOFT}} \right) \right) \qquad \mbox{for} \quad \frac{\hbar^2 |\bold{G}|^2 }{2 m_e} \gt \mathbf{ENCUTGWSOFT} }[/math]
Related Tags and Sections
PRECFOCK, ENCUT, ENCUTGW, GW calculations