ABINIT, PAW input variables:

List and description.

This document lists and provides the description of the name (keywords) of the input variables for runs based on the Projector Augmented Waves methodology, to be used in the main input file of the abinis code.

The new user is advised to read first the new user's guide, before reading the present file. It will be easier to discover the present file with the help of the tutorial.

When the user is sufficiently familiarized with ABINIT, the reading of the ~ABINIT/Infos/tuning file might be useful. For response-function calculations using abinis, the complementary file ~ABINIT/Infos/respfn_help is needed.

Copyright (C) 1998-2004 ABINIT group (DCA, XG, RC)
This file is distributed under the terms of the GNU General Public License, see ~ABINIT/Infos/copyright or http://www.gnu.org/copyleft/gpl.txt .
For the initials of contributors, see ~ABINIT/Infos/contributors .
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Files that describe other input variables:

Content of the file : alphabetical list of PAW input variables.


A.
B.
C.
D.
E.
F.
G.
H.
I.
J.
K.
L.
M.
N. ngfftdg  
O.
P. pawecutdg   pawlcutd   pawmqgrdg   pawnphi   pawntheta  
Q.
R.
S.
T.
U.
V.
W.
X.
Y.
Z.



ngfftdg
Mnemonics: Number of Grid points for Fast Fourier Transform : Double Grid
Characteristic:
Variable type: integer array ngfftdg(3)
Default :

Needed only when usepaw=1.
To be documented.



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pawecutdg
Mnemonics: PAW - Energy CUToff for the Double Grid
Characteristic: ENERGY
Variable type: real parameter
Default : 1.25 times ecut

Needed only when usepaw=1.
Define the energy cut-off for the fine FFT grid (that allow to transfer data from the normal, coarse, FFT grid to the spherical grid around each atom).
pawecutdg must be larger or equal to ecut. If equal to it, then no fine grid is used. The results are not very accurate, but the computations proceed quite fast.
The default value is sometimes a bit too low, but does not slow down the computation. The choice made for this variable DOES have a bearing on the numerical accuracy of the results, and, as such, should be the object of a convergence study. The convergence test might be made on the total energy or derived quantities, like forces, but also on the two values of the "Compensation charge inside spheres", a quantity written in the log file.



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pawlcutd
Mnemonics: PAW - 1+L angular momentum used to CUT the development in moments of the Densitites
Characteristic:
Variable type: integer parameter
The default is 10

Needed only when usepaw=1.
The expansion of the densities in angular momenta is performed up to l=pawlcutd-1.
The choice made for this variable DOES have a bearing on the numerical accuracy of the results, and, as such, should be the object of a convergence study. The convergence test might be made on the total energy or derived quantities, like forces, but also on the two values of the "Compensation charge inside spheres", a quantity written in the log file.



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pawmqgrdg
Mnemonics: PAW - Max. number of Q-space GRid points for psp for the Double Grid
Characteristic:
Variable type: integer parameter
The default is -1

Needed only when usepaw=1.
Same use as mqgrid, but for the fine grid, instead of the coarse grid.
If set to -1, the step corresponding to mqgrid for the coarse grid (defined by the energy cut-off ecut) is computed, and then, the same step is used for the fine grid (defined by the energy cut-off pawecutdg).



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pawnphi
Mnemonics: PAW - Number of PHI angles used to discretize the sphere around each atom.
Characteristic:
Variable type: integer parameter
The default is 13

Needed only when usepaw=1.
Number of phi angles (longitude) used to discretize the data on the atomic spheres. This discretization is completely defined by pawnphi and pawntheta.



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pawntheta
Mnemonics: PAW - Number of THETA angles used to discretize the sphere around each atom.
Characteristic:
Variable type: integer parameter
The default is 12

Needed only when usepaw=1.
Number of theta angles (latitude) used to discretize the data on the atomic spheres. This discretization is completely defined by pawntheta and pawnphi.



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Help files : New user's guide | Abinis (main) | Abinis (respfn) | Mrgddb | Anaddb | AIM (Bader) | Cut3D