How to calculate the dielectric function for metal using VAS
Posted: Fri Feb 26, 2016 10:25 am
Dear VASP users,
I want to study the optical properties of metal using VASP. I have two questions,
1)Is it correct to calculate the dielectric function just setting LOPTICS=.TRUE., or it is necessary to combine it with LRPA=.TRUE., when the RPA is involved?
2)I find that the dielectric function by ISMEAR = 1 and -5 totally different from each other. The latter seemed to diverge at the low frequencies, while the former does not. It makes me confused about which one is correct.
Thanks for your answer.
I want to study the optical properties of metal using VASP. I have two questions,
1)Is it correct to calculate the dielectric function just setting LOPTICS=.TRUE., or it is necessary to combine it with LRPA=.TRUE., when the RPA is involved?
2)I find that the dielectric function by ISMEAR = 1 and -5 totally different from each other. The latter seemed to diverge at the low frequencies, while the former does not. It makes me confused about which one is correct.
Thanks for your answer.