ENCUTGWSOFT

ENCUTGWSOFT = [real] 

Default: ENCUTGWSOFT	= ENCUTGW$\times 0.8$	for ALGO=ACFDT
	= ENCUTGW$\times 0.8$	as of VASP.6.3
	= ENCUTGW	else

Important: For vasp.6.3 and later releases ENCUTGWSOFT always defaults to ENCUTGW$\times 0.8$.

Descprition: The flag ENCUTGWSOFT sets the energy cutoff for response function, such that it allows to truncate the Coulomb kernel slowly between the energy specified by ENCUTGWSOFT and ENCUTGW.

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This usually leads to much smoother energy-volume curves in ACFDT calculations and MP2 calculations. The modified Coulomb kernel is in this case: $v_{\mathbf {G}}={\frac {4\pi e^{2}}{G^{2}}}{\frac {1}{2}}\left(1+\cos \left(\pi \,{\frac {{\frac {\hbar ^{2}G^{2}}{2m_{e}}}-\mathrm {ENCUTGWSOFT} }{\mathrm {ENCUTGW} -\mathrm {ENCUTGWSOFT} }}\right)\right)\qquad {\mbox{for}}\quad {\frac {\hbar ^{2}G^{2}}{2m_{e}}}>\mathrm {ENCUTGWSOFT}$

If LSCK is set to .TRUE., the squeezed Coulomb kernel is used instead of the cosine window:

$v_{\mathbf {G}}={\frac {4\pi e^{2}}{|{\mathbf {G}}|^{2}}}{\frac {1}{2}}\left(1+\cos \left(\pi \,{\frac {{\frac {\hbar ^{2}|{\mathbf {G}}|^{2}}{2m_{e}}}-\mathrm {ENCUTGWSOFT} }{\mathrm {ENCUTGW} -\mathrm {ENCUTGWSOFT} }}\right)\right)\qquad {\mbox{for}}\quad G_{min}<G<G_{max}$

where $\hbar ^{2}G_{max}=\mathrm {ENCUTGW}$

Related Tags and Sections

PRECFOCK, ENCUT, ENCUTGW, GW calculations, LSCK

Examples that use this tag

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