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: $v_{\bold{G}} = \frac{4 \pi e^2} {G^2} \frac{1}{2} \left( 1 + \cos \left( \pi \, \frac{ \frac{\hbar^{2} G^2 }{2 m_e} - \mathrm{ ENCUTGWSOFT} }{ \mathrm{ENCUTGW} - \mathrm{ENCUTGWSOFT}} \right) \right) \qquad \mbox{for} \quad \frac{\hbar^2 G^2 }{2 m_e} > \mathrm{ENCUTGWSOFT}$

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

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

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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