ABINIT Discussion Forums

Dear all:
I am new with ab initio pseudo potential method. In order to study the pressure effect of the electronic properties of CaS in the B1 phase and B2 phase. I am using the GGA (PBE) HGH pseudo potential in the Abinit site. The question is from pseudo potential:
When employing these pseudo potential to study the pressure effect, which parameter controlled in the pseudo potential for example ( from TM pseudo potential the cutoff radius smaller for high pressure study to avoid overlap of the pseudo region …!!!!)
Or:
From HGH pseudo potential in the abinit site is generated at 0 pressures, is it correct to employing these pseudo potential at high pressure?
Are they any document to explain this point?

Thanks

The basic rule is no overlapping spheres between pseudopotentials.

Check the radii in the HGH files (r_XY) to find the largest one, and compare to inter-atomic distances

d_AB >= r_A + r_B

In practice a small overlap is usually not problematic, but effects can be randomly dangerous.

For high pressures you often need tailor-made pseudopotentials, e.g. with fhi98pp or opium using small cutoff radii.

Matthieu