[Pw_forum] BFGS Relaxation

[Kanak Datta]

Dear researchers

For BFGS relaxation of bilayer WS2..I have been using the following code...
&CONTROL
      calculation = 'relax',
     restart_mode = 'from_scratch',
           outdir = 'D:\QuantumEspresso\Quantum ESPRESSO 64-bit
5.1.2-mpich2\WS2Bilayer\outdir',
           prefix = 'WS2Bilayer',
/
&SYSTEM
 ibrav = 0,
a = 1.86,
nat = 6,
ntyp = 2,
occupations = 'smearing',
smearing = 'methfessel-paxton',
degauss = 0.001,
nspin=2,
ecutwfc = 20,
ecutrho = 160,
nbnd = 30,
starting_magnetization=0.6,
 /

&ELECTRONS
conv_thr = 1.0d-5,
mixing_mode = 'plain',
mixing_beta = 0.7,
diagonalization = 'david',
diago_full_acc = .true.
 /
&IONS
ion_dynamics      = 'bfgs',
pot_extrapolation = 'second_order',
wfc_extrapolation = 'second_order',
upscale           = 100,
/
CELL_PARAMETERS
1.5 0.8660254038 0.00000
1.5 -0.8660254038 0.00000
0.0000 0.00000 15.0
ATOMIC_SPECIES
W 183.84 W.pbe-hgh.UPF
S 32.066 S.pbe-hgh.UPF
ATOMIC_POSITIONS (angstrom)
S       0.000000000  0.000000000   5.15
S       0.000000000  0.000000000   2
W       1.818653348  0.000000000   3.575
S       0.000000000  0.000000000   8.6
S       0.000000000  0.000000000   10.175
W       1.818653348  0.000000000   11.75
K_POINTS {automatic}
24 24 1   0 0 0


1. I just wanted to know whether the cutoff values are ok or not.......As I
am from EEE background..I have very little knowledge on these things.....
2. Besides should the van der waals corrections be applied in relaxation
part from the beginning?

Thanks in advance.

Sincerely yours
kanak
BUET
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