Lattice vectors IN OUTCAR File

[Iyyapparajan]

Dear VASP users,
The lattice vectors are written differently at various places in the beginning of OUTCAR file for my system. Can any one please tell why it is so ?

LATTYP: Found a simple monoclinic cell.
ALAT = 17.1355026082
B/A-ratio = 0.5964422500
C/A-ratio = 1.9503186259
COS(beta) = -0.9850998462

Lattice vectors:

A1 = ( -3.9161500191, 0.0000000000, -16.6820028373)
A2 = ( 0.0000000000, -10.2203377303, 0.0000000000)
A3 = ( 1.9284186177, 0.0000000000, 33.3640056746)


Analysis of symmetry for initial positions (statically):
=====================================================================
Subroutine PRICEL returns following result:

LATTYP: Found a base centered monoclinic cell.
ALAT = 5.9038812434
B/A-ratio = 1.7311218348
C/A-ratio = 3.2788165264
COS(beta) = -0.2537481355

Lattice vectors:

A1 = ( 2.9519406217, 5.1101688652, 0.0000000000)
A2 = ( 2.9519406217, -5.1101688652, 0.0000000000)
A3 = ( -9.8200310854, 0.0000000000, -16.6820028373)

2 primitive cells build up your supercell.


Routine SETGRP: Setting up the symmetry group for a
simple monoclinic supercell.


Subroutine GETGRP returns: Found 4 space group operations
(whereof 4 operations were pure point group operations)
out of a pool of 4 trial point group operations.


The static configuration has the point symmetry C_2h.


Analysis of symmetry for dynamics (positions and initial velocities):
=====================================================================
Subroutine PRICEL returns following result:
LATTYP: Found a base centered monoclinic cell.
ALAT = 5.9038812434
B/A-ratio = 1.7311218348
C/A-ratio = 3.2788165264
COS(beta) = -0.2537481355

Lattice vectors:

A1 = ( 2.9519406217, 5.1101688652, 0.0000000000)
A2 = ( 2.9519406217, -5.1101688652, 0.0000000000)
A3 = ( -9.8200310854, 0.0000000000, -16.6820028373)

2 primitive cells build up your supercell.


Routine SETGRP: Setting up the symmetry group for a
simple monoclinic supercell.


Subroutine GETGRP returns: Found 4 space group operations
(whereof 4 operations were pure point group operations)
out of a pool of 4 trial point group operations.


The dynamic configuration has the point symmetry C_2h.





Static calculation
charge density and potential will be updated during run
spin polarized calculation
Variant of blocked Davidson
Davidson routine will perform the subspace rotation
perform sub-space diagonalisation
after iterative eigenvector-optimisation
modified Broyden-mixing scheme, WC = 100.0
initial mixing is a Kerker type mixing with AMIX = 0.4000 and BMIX = 1.0000
Hartree-type preconditioning will be used
using additional bands 138
reciprocal scheme for non local part
use partial core corrections
calculate Harris-corrections to forces
(improved forces if not selfconsistent)
use gradient corrections
use of overlap-Matrix (Vanderbilt PP)
Gauss-broadening in eV SIGMA = 0.10







--------------------------------------------------------------------------------------------------------


energy-cutoff : 400.00
volume of cell : 1006.59
direct lattice vectors reciprocal lattice vectors
5.903881421 0.000000000 0.000000000 0.169380096 0.000000000 0.020182357
0.000000000 10.220337730 0.000000000 0.000000000 0.097844125 0.000000000
-1.987731401 0.000000000 16.682002837 0.000000000 0.000000000 0.059944841

length of vectors
5.903881421 10.220337730 16.800008773 0.170578265 0.097844125 0.059944841







The POSCAR lattice vectors is as follows

5.9038814205271279 0.0000000000000000 0.0000000000000000
0.0000000000000000 10.2203377303197840 0.0000000000000000
-1.9877314014173515 0.0000000000000000 16.6820028373031022


Kindly help me any one one if you know...

Thanking you,

[admin]

In POSCAR you have defined a unit cell.
VASP found that your cell is made of two
smaller cells with lattice vectors different
from those of the supercell.
However, the calculation uses the lattice vectors
as defined in POSCAR.

[Iyyapparajan]

Dear Admin,

Thank you very much for your reply. For 42 atoms primitive unit cell, a warning is obtained at the beginning of the OUTCAR file. We are doing calculation for primitive monoclinic cell. The warning below states the following
Tried to take original basis but could not verify dimensions!

Since it is a warning, I think it can be ignored. Will it effect the calculations ?

The OUTCAR and POSCAR lines are below...

Warning from LATTYP: Got some problem with cell dimensions!
Tried to take original basis but could not verify dimensions!
LATTYP: Found a base centered monoclinic cell.
ALAT = 5.9038814200
B/A-ratio = 1.7311217846
C/A-ratio = 3.2788164592
COS(beta) = -0.2537481478

Lattice vectors:

A1 = ( 2.9519407100, 5.1101688700, 0.0000000000)
A2 = ( 2.9519407100, -5.1101688700, 0.0000000000)
A3 = ( -9.8200314400, 0.0000000000, -16.6820028400)



direct lattice vectors reciprocal lattice vectors
2.951940710 -5.110168870 0.000000000 0.169380096 -0.097844125 0.020182357
2.951940710 5.110168870 0.000000000 0.169380096 0.097844125 0.020182357
-1.987731400 0.000000000 16.682002840 0.000000000 0.000000000 0.059944841

length of vectors
5.901506573 5.901506573 16.800008776 0.196647952 0.196647952 0.059944841





The POSCAR lattice vectors are as follows :
1.000
2.95194071 -5.11016887 0.00000000
2.95194071 5.11016887 0.00000000
-1.98773140 0.00000000 16.68200284

Kindly let me know the calculations and lattice vectors are Ok..

Thanking you,
Iyyappa Rajan P

[admin]

Yes, you can ignore the warning.
The vectors seem to be OK.

[Iyyapparajan]

Respected Admin,
Thank you very much for your reply