how to choose Pseudopotential

[Jenny]

Hello.

Recently, I tried to relax my unit cell. And I found if I used different pseudopotential and basis set, the optimized geometry would be different with same initial configuration of unit cell. For NC-HGH I used Tier 5 as basis set and for NC-FHI I used DoubleZetaPolarized. May I ask what's the difference between NC-FHI and NC-HGH? If I'd like to optimize the geometry and calculate the transmission spectrum of CNT and Cu composite, which pseudopotential should I use in these situation?

Thanks.

Jenny

[kstokbro]

Both are norm conserving pseudo potentials. Usually the hgh are harder, thus you need a higher mesh cutoff for the hgh pseudo potentials.