[Wien] Questions on the quantitative understanding of DOS and partial DOS

[J. K. Balamurugan]

Dear WIEN2k developers and users,

I have some problem in quantitative understanding the DOS and partial DOS
plots/data. I post the question with a case assumption of room temperature
(RT) structure of BaTiO3. As it is well known BaTiO3 has tetragonal
structure at RT. Now, Ba and Ti has one site and O has two sites. If the
DOS & partial DOS are calculated for BaTiO3, I will get total DOS for the
unit cell which contains one formula unit of BaTiO3. I will also get
partial DOS of Ba, Ti and O1 and O2 (in terms of total and from individual
orbital contribution like s, p and d whichever are applicable.) Here are my
questions:

1. Will the sum of total DOS individual atoms [i.e., total DOS of (Ba + Ti
+ O1 + O2)] be exactly equal to total DOS of the unit cell? If the answer
is No, why?

2. Will the total DOS of any specific atom, say Ti, will be exactly equal
to the sum of orbital contributions [i.e., partial DOS of (Ti-s + Ti-p +
Ti-d)]?  If the answer is No, why?

Another related question: Let us assume a hypothetical structure where in I
have two formula units of BaTiO3 in a unit cell. That is the unit cell has
Ba2Ti2O6. Now the question is the following:
3. Should I need to multiply 2 to the total DOS of individual atoms {i.e.,
2*[total DOS of (Ba + Ti + O1 + O2)]} to get the total DOS of the unit cell
with two formula unit? Will this sum be exactly equal to the actual total
DOS of the unit cell which we get as it is from the calculations?

Please explain me to clear these my questions. I wish also to get into
reading any material/user guide/article/document which could help me to
have a complete understanding on this issue.

Thanks.

With kind regards,
K. Balamurugan.




-- 
*K. Balamurugan
Pittsburgh, USA.
+1 412 961 5055*
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