In data 15 luglio 2009 alle ore 10:45:12, ambavale sagar <sagarambavale at yahoo.co.in> ha scritto: > If I use uspp along with ncpp in the calculations, which would be > changes in the values of ecut and ecutrho?
It depends on the details of the various pseudopotentials, it is likely that one of the norm-conserving will require the higher ecutwfc (and that values will have to be used for all the calculations). Under this assumption, you have to test the ultrasoft pseudopotential with this high values of ecutwfc and test if it is well converged with respect to ecutrho. Let's make an example, "->" means "is well converged at": S -> ecutwfc = 50Ry C -> ecutwfc = 60Ry H -> ecutwfc = 45Ry => you'll have to take ecutwfc=60, which imply ecutrho >= 60*4 = 240 case 1: Ag -> ecutwfc = 25, ecutrho = 200 ==> you just take ecutwfc=60, and ecutrho will be large enough for the Ag pseudopotential too case 2: Ag -> ecutwfc = 36, ecutrho = 360 ==> you have to take ecutwfc=60 (as required by the C pseudopotential) and ecutrho=360 (as required by the Ag ultrasoft-pseudopotential) best regards -- Lorenzo Paulatto SISSA & DEMOCRITOS (Trieste) phone: +39 040 3787 511 skype: paulatz www: http://people.sissa.it/~paulatto/ *** save italian brains *** http://saveitalianbrains.wordpress.com/
