ENCUTGWSOFT

ENCUTGWSOFT = [real] (energy cutoff for response function)

Default: ENCUTGWSOFT	= ENCUTGW $\times 0.8$	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: $v_{\mathbf {G}}={\frac {4\pi e^{2}}{|{\mathbf {G}}|^{2}}}{\frac {1}{2}}\left(1+\cos \left(\pi \,{\frac {{\frac {\hbar ^{2}|{\mathbf {G}}|^{2}}{2m_{e}}}-\mathbf {ENCUTGWSOFT} }{\mathbf {ENCUTGW} -\mathbf {ENCUTGWSOFT} }}\right)\right)\qquad {\mbox{for}}\quad {\frac {\hbar ^{2}|{\mathbf {G}}|^{2}}{2m_{e}}}>\mathbf {ENCUTGWSOFT}$