LSCK: Difference between revisions
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\qquad \mbox{for} \quad \mathrm{ENCUTGWSOFT}=\frac{\hbar^2G_{min}^2}{2m_e}<\frac{\hbar^2 G^2}{2m_e}<\frac{\hbar^2G_{max}^2}{2m_e}=\mathrm{ENCUTGW}</math> | \qquad \mbox{for} \quad \mathrm{ENCUTGWSOFT}=\frac{\hbar^2G_{min}^2}{2m_e}<\frac{\hbar^2 G^2}{2m_e}<\frac{\hbar^2G_{max}^2}{2m_e}=\mathrm{ENCUTGW}</math> | ||
This kernel 'squeezes' the contributions from large wave vectors <math>G>G_{max}</math> into the window given by {{TAG|ENCUTGWSOFT}}. Effectively, this extrapolates the random-phase-approximation–correlation energy to the {{TAG|ENCUTGW}} <math>\to \infty</math> limit, assuming that the basis-set-incompleteness error falls off as <math>1/</math>{{TAG|ENCUTGW}}<math>^{3/2}</math>. | This kernel 'squeezes' the contributions from large wave vectors <math>G>G_{max}</math> into the window given by {{TAG|ENCUTGWSOFT}}. Effectively, this extrapolates the random-phase-approximation–correlation energy to the {{TAG|ENCUTGW}} <math>\to \infty</math> limit, assuming that the basis-set-incompleteness error falls off as <math>1/(</math>{{TAG|ENCUTGW}}<math>)^{3/2}</math>. | ||
== Related tags and articles == | == Related tags and articles == | ||
{{TAG|ENCUTGW}}, | {{TAG|ENCUTGW}}, | ||
Revision as of 11:43, 14 April 2026
LSCK = [logical]
Default: LSCK = .FALSE.
| Important: Up to vasp.6.2, the default was LSCK= .TRUE. |
Description: LSCK=.True. switches on the squeezed Coulomb kernel.
If LSCK is set to .TRUE., the squeezed Coulomb kernel is used instead of the cosine window [1]:
[math]\displaystyle{ v_{G} = 4 \pi e^2 \frac{ (G_{max}-G_{min})(G_{max}-G) }{ (G_{min}^2 - G(2G_{min}-G_{max}))^2 } \qquad \mbox{for} \quad \mathrm{ENCUTGWSOFT}=\frac{\hbar^2G_{min}^2}{2m_e}<\frac{\hbar^2 G^2}{2m_e}<\frac{\hbar^2G_{max}^2}{2m_e}=\mathrm{ENCUTGW} }[/math]
This kernel 'squeezes' the contributions from large wave vectors [math]\displaystyle{ G>G_{max} }[/math] into the window given by ENCUTGWSOFT. Effectively, this extrapolates the random-phase-approximation–correlation energy to the ENCUTGW [math]\displaystyle{ \to \infty }[/math] limit, assuming that the basis-set-incompleteness error falls off as [math]\displaystyle{ 1/( }[/math]ENCUTGW[math]\displaystyle{ )^{3/2} }[/math].
Related tags and articles
ENCUTGW, GW calculations ACFDT/RPA calculations