[Wien] Finding the preferred site

[Seyyed Mojtaba Zareii (Alavi Sadr)]

Hi dear wien2k users
I want to investigate the effect of Hydrogen absorption in
LaNi4.5Sn0.5 compound as H atom will occupy the interstitial site to
form LaNi4.5Sn0.5H hydride. I could simulate parent compound,
LaNi4.5Sn0.5, successfully, but I have a problem with finding the
preferred occupied site for H atom:
It seems that there are two approaches to find the preferred site for
H to be occupied as follows:
1-	One can find the preferred site occupation with evaluating the
total energy of the system for different positions of the H site and
finding more negative energy via optimization program (energy versus
volume).
        In this way, we don’t use the mini-position program (force
minimization for H atom).
OR
2-	Putting H atom in the possible different sites, first one should do
mini-position program to find the relaxed location for H atom where
Hellmann-Feynman forces were minimized. After obtaining the relaxed
Hydrogen position for each model, do the optimization program (Energy
versus Volume) for the same structures to find the structure with more
negative energy as preferred site for H.
Which approach is correct? Is there any approach for this problem?

Thank you
Zareii