[Pw_forum] charged defect

[ali kazempoor]

Dear all
 I want to study O vacancy in TiO2 bulk . So , I need to know about different charged vacancy and then simulation of the large supercell containing the vacancy. I have two questions :
1- How can I  find that how many possibilities are exist for charged vacancies ( I mean that wheather I have nuetral O or O+ or O- or etc).
Is these charged state related to experimental data or only determind by theory?
2- After, How can I make supercell input file that has charged vacancy. I mean that which parameter shoud be modified or added to make a supercell include charged defect?  and how can I check they are correct?

Thanks a lot 
Ali Kazempour,Isfahan University of technology,physics Dept