Pd d band vacancies
Posted: Fri Oct 05, 2007 2:48 pm
Hi all,
I tried to calculate the Pd d band vacancies for bi metallic alloy Pd-Co.
For Pd, Pd3Co, PdCo and PdCo3 I built surface 111 and a supercell 2x2x1.
Further I performed a Density of States calculations with relaxations of the two top atoms layers of the surface model.
For one Pd atom of the top layer for each case (Pd, Pd3Co, PdCo and PdCo3), I calculated the Number Of availble States (NoS) with the integration of the density of states of the d band over the entire range in energy. Then I calculated the electron population (EP) in the d band with integration of the d band up to the fermi level.
I calculated d band vacancies with:
Vacancies = NoS - EP, is it correct ?
The problem is that the number of vacancies decrease when Co loading increase, it's not coherent with experimental work from litterature performed with XAS or XANES where the tendency is the reverse.
Where my problem could coming from ?
Thanks
Phoudha
I tried to calculate the Pd d band vacancies for bi metallic alloy Pd-Co.
For Pd, Pd3Co, PdCo and PdCo3 I built surface 111 and a supercell 2x2x1.
Further I performed a Density of States calculations with relaxations of the two top atoms layers of the surface model.
For one Pd atom of the top layer for each case (Pd, Pd3Co, PdCo and PdCo3), I calculated the Number Of availble States (NoS) with the integration of the density of states of the d band over the entire range in energy. Then I calculated the electron population (EP) in the d band with integration of the d band up to the fermi level.
I calculated d band vacancies with:
Vacancies = NoS - EP, is it correct ?
The problem is that the number of vacancies decrease when Co loading increase, it's not coherent with experimental work from litterature performed with XAS or XANES where the tendency is the reverse.
Where my problem could coming from ?
Thanks
Phoudha