[Pw_forum] Cu US PP with PBE exchange

[Hong, SamPyo]

Hello,
Just for a test purpose, I picked up the pseudopotential
'Cu.pbe-d-rrkjus.UPF' for Cu bulk, which I downloaded from web.
The known experimental a0 is 3.61 Angstrom but I could get at best 3.80
angstrom, which is huge off from the value.
I wonder why this PP performs that poorly.....I think ecut of 20 ryd and
k-sampling of 15x15x15 should be enough for test.
Does anybody have an idea?

Best regards,

Sampyo