[gpaw-users] X-ray adsorption calculation-convergence

[Xiao Jianping]

Dear gpaw-users,

I want to calculate XAS of ZnO. Firstly I setup core hole paw files for 
Zinc and oxygen (fch1s). In this case I want to implement Zinc K-shell 
transition. I am unclear on the occupation. The Zn2O2 primitive 
structure has 30*2+8*2=76 electrons. How I should set occupation 
parameters? (occupation is for valence electrons or core electrons and 
both ?) The following case I calculated is not converged. Thank you very 
much!
----------------------------------------------------------------------------------
/atoms = Atoms(symbols='Zn2O2',/
/                positions=[/
/                (-0.949,-1.643,0),/
/                (-1.89,0,2.621),/
/                (-0.945,-1.643,2.006),/
/                (-1.89,0,-0.615)],/
/                cell=[(2.85,-1.64,0),(0,3.29,0),(0,0,5.24)],/
/                pbc=(1,1,1))/
/calc  = GPAW(h=0.2,/
/             txt='ZnO_exc.txt',/
/             xc='PBE',/
/             kpts=(4, 4, 4),/
/             nbands = -30,/
/             maxiter=120,/
/             charge=-2,/
/             spinpol=True,/
/             occupations=FermiDirac(74.0, fixmagmom=True),/
/             convergence={'energy': 0.001, # eV/
/                        'density': 1.0e-5,/
/                        'eigenstates': 1.0e-9},/
/             mixer=Mixer(beta=0.5, nmaxold=5, weight=70.0),/
/             setups={0: 'fch1s',1: 'fch1s'})/

/atoms[0].magmom = 1/
/atoms[1].magmom = 1/
----------------------------------------------------------------------------------

Best regards
Jianping
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