[Pw_forum] LD1 - Choosing a 3D rcutus

[Michael Vargas (michaelv@Princeton.EDU)]

Hello, I'm pretty new at using this program.  I am trying to make an US-PP for Oxygen over a large energy range.  I am using an unbound 3D for the local channel.  I was wondering if anyone could give me some insight on how to choose my cut-off radius for this?  I am currently using about 1.5 bohr for the rcut and rcutus, as this works well for agreement in the logarithmic derivatives, but I'm not sure if there should be some deeper reason.  This is an unbound 3D, so I can't see the wavefunction to guess at a reasonable radius.  Thank you for any help you can give.  --  Mike