LSCK

LSCK = [logical]
Default: LSCK = .FALSE.  Up to vasp.6.2, the default was LSCK = .TRUE.

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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 :

$v_{G} = 4 \pi e^2 \frac{ (G_{max}-G_{min})(G_{max}-G) }{ (G_{min}^2 - G(2G_{min}-G_{max}))^2 } \qquad \mbox{for} \quad \mathrm{ENCUTGWSOFT}=\frac{\hbar^2G_{min}^2}{2m_e}<\frac{\hbar^2 G^2}{2m_e}<\frac{\hbar^2G_{max}^2}{2m_e}=\mathrm{ENCUTGW}$

This kernel 'squeezes' the contributions from large wave vectors $G>G_{max}$ into the window given by ENCUTGWSOFT. Effectively, this extrapolates the random-phase-approximation–correlation energy to the ENCUTGW $\to \infty$ limit, assuming that the basis-set-incompleteness error falls off as $1/$ENCUTGW$^{3/2}$.

Related tags and articles

ENCUTGW, GW calculations ACFDT/RPA calculations

Examples that use this tag

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