Current version of USpp2Abinit :v2.4.0

Available for Abinit v5.4.3+
See this note for use with previous versions of Abinit

To obtain PAW atomic data for Abinit we proceed as follows:
    - We patch D. Vanderbilt's USPP package in order to make it generate PAW atomic data in Abinit's format (in addition to ultrasoft pseudopotentials).
    - "Patched" USPP is directly useable to produce PAW atomic data from normal USPP input files.

1. What you need:

• USPP ultrasoft pseudopotentials generator (version 7.3.6 or higher)
  This code is written in Fortran 77

• USpp2Abinit add-on tu USPP
  This code is written in Fortran 90

• A Linux/Unix workstation with (at least) following tools:
  Fortran 90 compiler with F77 libraries, sed stream editor, make utility.

2. Preliminary steps: patching USPP:

• Download USPP package. You can find it here. Be sure to download version 7.3.6 or higher (including some modif. for Abinit).
• Extract USPP (in some /uspp-xyzdirectory)

• Download USpp2Abinit package. You can find it here (fully compatible with ABINIT v6.1.0+; partly compatible with ABINIT v5.4.3+).
  See this note for use of USpp2Abinit with versions 4.6.x-6.0.x of ABINIT.
  Here USpp2Abinit for Abinit v4.3.x-v.4.5.x (buggy !, only for tests).

• Extract Uspp2Abinit into USPP directory (in /uspp-xyz/USpp2Abinit.vx.y.z directory).
  Note that you also get a new  /uspp-xyz/utils-uspp directory

• Go into /uspp-xyz/Uspp2Abinit.vx.y.z directory and edit Makefile file; modify it according to your machine specifications.
• Into /uspp-xyz/Uspp2Abinit.vx.y.z directory,

3. Generating a  PAW "pseudopotential file" for Abinit:

• Simply use USPP as if you wanted to generate an ultrasoft pseudopotential !

Go into /uspp-xyz/Work directory; browse down sub-directories, selecting chemical specie and density functional (LDA, GGA).
Type make clean; make
If you encounter some error during execution, look for an error message in the ??_ae.out or ??_ps.out file; if the error message is not explicit enough, look at Doc/TUTORIAL (most of the problems are referenced inside).

• And you get a X.abinit.paw file (X=generic name) directly useable by Abinit !
• Additional options:

4. Additional remarks:

• You can as a first step use input files (*.adat files) distributed by D. Vanderbilt on his web site.
  But we recommend to make additional tests before using those input files. PAW formalism is a bit different from US pseudopotentials one and can induce a different behaviour of atomic data.
• The choice of a density functionalis limited by functionals included in USPP package and in Abinit.
  To be used a density functional model must be incorporated into both packages.
  Only four functionals are programmed in USPP and Abinit together: Ceperley-Adler (LDA), Wigner (LDA), Hedin-Lundqvist (LDA), Perdew-Burke-Ernzerhof 96 (GGA)
• In order to check the validity of atomic data produced by USPP, a simple test is the comparison of the logarithmic derivatives of wave functions (exact ones compared to pseudo ones).
  A simple PYTHON script pltlogd is provided within USpp2Abinit package in /uspp-xyz/utils-uspp directory to plot these derivatives. It uses the ??.logd file produced by USPP.
  Just type: pltlogd file.logd l,        where l is an angular momentum (0, 1, 2, or 3).

5. References:

[2] Implementation of Ultra-Soft Pseudopotentials in Ab-initio Molecular Dynamics,
K. Laasonen, R. Car, C. Lee, D. Vasnderbilt, Phys. Rev. B 43 (Rapid Communications), 6796 (1991)

6. Contacts:

In case of problem or questions contact the authors.

Marc Torrent
Francois Jollet
Département de Physique Théorique et Appliquée
CEA, DAM, DIF
F-91127 Arpajon
France

Last modification : may 11th  2010