[Pw_forum] xspectra calculation

[Matteo Calandra]

Dear Min Wu,

 >
 >It seems i have found the problem. It's not the problem of the
 >xcoordcrys. I set it as .true. and the polarization vectors are 
(0,0,1) >and
 >(0,1,0). The xray k vector is the default value (1,0,0).
 >BTW, can we use the same vector for polarization and xay k moment?
 >e.g. Both of them are (1,0,0). Is it OK?

Of course epsilon and k MUST be ortogonal otherwise what you are doing
is meaningless. If you calculate the dipolar part only then
the k-vector is not used and can take any value.

 >
 >The problem i found is that i set the "cut_occ_states" = .true.
 >Then it cut all the occupied state that i expected to see.
 >When i reset it to .false., i saw the expected peak.
 >

Maybe your ef_r is not in the correct units... Of course you put the
Fermi level in the presence of a core-hole, don't you ?

 >I have another problem, what does the "ef_r" do in the calculation?
 >For instance, i got fermi level of -5 eV with scf calculation.
 >The i set ef_r= -5/13.6 Ry. Then, in the calculated xspectra data, 
 >where is
 >the Fermi level? It is ajusted to 0 eV, or still is the -5 eV?
 >

zero, the energies are simply shifted.

M.

-- 
* * * *
Matteo Calandra, Charge de Recherche (CR1)
Institut de Minéralogie et de Physique des Milieux Condensés de Paris
Université Pierre et Marie Curie, tour 16, case 115
4 Place Jussieu, 75252 Paris Cedex 05 France
Tel: +33-1-44 27 52 16       Fax: +33-1-44 27 37 85
http://www.impmc.jussieu.fr/~calandra