Re: Spiorbit coupling ( No.1 ) 
 Date: 2021/08/01 11:48
 Name: T. Ozaki
 Hi,
The case: scf.spinpolarization off scf.spinorbit.coupling off
corresponds to the collinear spinunpolarized calculation with scalar relativistic pseudopotentials generated with taking account of the jdegeneracy as
V_l = ( (l+1)*V_{l+1/2} + l*V_{l1/2})/(2*l+1)
On the other hand, the case: scf.spinpolarization NC scf.spinorbit.coupling on specifying zeros in scf.so.factor
corresponds to the noncollinear calculation with zero spinorbit coupling, where the pseudpotentials are generated by
sum = (V_{l+1/2} + V_{l1/2})/2 dif = (V_{l+1/2}  V_{l1/2})/2
V'_{l+1/2} = sum + scf.so.factor * dif V'_{l1/2} = sum  scf.so.factor * dif
Therefore, if a system is nonmagnetic, the difference can be attributed to how to generate the scalar relativistic pseudopotentials.
These manipulation can be confirmed around lines 902925 of SetPara_DFT.c.
Regards,
TO

