[Pw_forum] Confusion in choosing rlderiv

[Paolo Giannozzi]

On Jul 13, 2011, at 8:18 , karan deep wrote:

> rlderiv( rd) should be of the order of the ionic or covalent radius,
> and larger than any of the rc ’s (cut of radius for each pseudo  
> wave function)

it is not a strict rule, as long as rd is not much smaller than rc
>
> also according to  some posts here, the value of rd should be in  
> the order of
> half a typical bond-bond distance. is it mean that rc's should be  
> less then this
> value ???

it is preferrable that the "core" regions (i.e. the region of space  
where the pseudo
and all-electron orbitals appreciably differ) do not overlap. Again,  
not a strict rule.

P.
---
Paolo Giannozzi, Dept of Chemistry&Physics&Environment,
Univ. Udine, via delle Scienze 208, 33100 Udine, Italy
Phone +39-0432-558216, fax +39-0432-558222