[Pw_forum] vc-relax of a 60 atom supercell
Elie Moujaes
elie.moujaes at hotmail.co.uk
Mon Jun 7 22:19:33 CEST 2010
Dear all, I am trying to relax a 60 atom supercell of graphene using vc-relax.
(1) I want the relaxation to be with respect to both atomic coordinates and supercell vectors, Is vc-relax the correct calculation to use.
(2) I used a vc relax to my superstructure but the programm stopped at the 9th iteration (well it did not stop literally but the calculations ended with no 9th iterations and no converged results along with errors related to the c_bands):
Initial potential from superposition of free atoms
Check: negative starting charge= -1.223428
starting charge 239.99756, renormalised to 240.00000
negative rho (up, down): 0.122E+01 0.000E+00
Starting wfc are 240 atomic wfcs
total cpu time spent up to now is 11871.45 secs
per-process dynamical memory: 384.3 Mb
Self-consistent Calculation
iteration # 1 ecut= 10.00 Ry beta=0.05
Davidson diagonalization with overlap
ethr = 1.00E-02, avg # of iterations = 6.7
negative rho (up, down): 0.117E+01 0.000E+00
total cpu time spent up to now is 47489.34 secs
total energy = -643.54940490 Ry
Harris-Foulkes estimate = -643.62010992 Ry
estimated scf accuracy < 4.23960826 Ry
iteration # 2 ecut= 10.00 Ry beta=0.05
Davidson diagonalization with overlap
ethr = 1.77E-03, avg # of iterations = 2.2
negative rho (up, down): 0.109E+00 0.000E+00
total cpu time spent up to now is 64468.90 secs
total energy = -642.58636317 Ry
Harris-Foulkes estimate = -643.55371202 Ry
estimated scf accuracy < 3.93330724 Ry
iteration # 3 ecut= 10.00 Ry beta=0.05
Davidson diagonalization with overlap
ethr = 1.64E-03, avg # of iterations = 2.0
negative rho (up, down): 0.148E+00 0.000E+00
total cpu time spent up to now is 85947.86 secs
total energy = -642.70459925 Ry
Harris-Foulkes estimate = -642.70343771 Ry
estimated scf accuracy < 0.07850650 Ry
iteration # 4 ecut= 10.00 Ry beta=0.05
Davidson diagonalization with overlap
c_bands: 1 eigenvalues not converged
c_bands: 1 eigenvalues not converged
c_bands: 1 eigenvalues not converged
c_bands: 1 eigenvalues not converged
c_bands: 1 eigenvalues not converged
ethr = 3.27E-05, avg # of iterations = 12.4
negative rho (up, down): 0.151E+00 0.000E+00
total cpu time spent up to now is 112929.09 secs
total energy = -642.71219905 Ry
Harris-Foulkes estimate = -642.71283310 Ry
estimated scf accuracy < 0.06999785 Ry
iteration # 5 ecut= 10.00 Ry beta=0.05
Davidson diagonalization with overlap
ethr = 2.92E-05, avg # of iterations = 1.1
negative rho (up, down): 0.349E+00 0.000E+00
total cpu time spent up to now is 135493.02 secs
total energy = -642.68724348 Ry
Harris-Foulkes estimate = -642.71241729 Ry
estimated scf accuracy < 0.06752485 Ry
iteration # 6 ecut= 10.00 Ry beta=0.05
Davidson diagonalization with overlap
c_bands: 1 eigenvalues not converged
c_bands: 1 eigenvalues not converged
ethr = 2.81E-05, avg # of iterations = 8.8
negative rho (up, down): 0.397E+00 0.000E+00
total cpu time spent up to now is 167131.43 secs
total energy = -642.68305797 Ry
Harris-Foulkes estimate = -642.69027767 Ry
estimated scf accuracy < 0.02138677 Ry
iteration # 7 ecut= 10.00 Ry beta=0.05
Davidson diagonalization with overlap
c_bands: 1 eigenvalues not converged
c_bands: 1 eigenvalues not converged
ethr = 8.91E-06, avg # of iterations = 9.6
negative rho (up, down): 0.375E+00 0.000E+00
total cpu time spent up to now is 195521.38 secs
total energy = -642.68507799 Ry
Harris-Foulkes estimate = -642.68373726 Ry
estimated scf accuracy < 0.01412971 Ry
iteration # 8 ecut= 10.00 Ry beta=0.05
Davidson diagonalization with overlap
ethr = 5.89E-06, avg # of iterations = 1.2
negative rho (up, down): 0.241E+00 0.000E+00
total cpu time spent up to now is 217886.22 secs
total energy = -642.68307655 Ry
Harris-Foulkes estimate = -642.68513864 Ry
estimated scf accuracy < 0.01367803 Ry
iteration # 9 ecut= 10.00 Ry beta=0.05
The input file is:
&control
prefix='GB mgraphene',
calculation='vc-relax',
restart_mode='from_scratch',
pseudo_dir = '/exp/home/caiapo/emoujaes/espresso/espresso-4.1.3/pseudo/',
outdir='/exp/home/caiapo/emoujaes/Moujaes-Results/',
tstress = .true.,
tprnfor = .true.,
disk_io = 'low'
/
&system
ibrav= 0, celldm(1) =1.88972, nat=60, ntyp= 1, ecutwfc = 110D0 ,occupations='smearing', smearing='methfessel-paxton', degauss=0.01
/
&electrons
conv_thr=1.D-8,
mixing_beta=0.05D0,
mixing_mode='local-TF',
diagonalization='david'
/
& ions
ion_dynamics = 'bfgs',
pot_extrapolation = 'second-order',
wfc_extrapolation = 'second-order'
/
& cell
cell_dynamics = 'bfgs',
press_conv_thr = 0.1
ATOMIC_SPECIES
C 12.0107 C.pz-vbc.UPF
ATOMIC_POSITIONS angstrom
C -11.737980 -3.561278 0.000000
C -11.057718 -1.211571 0.000000
C -12.450000 -7.189838 0.000000
C -12.450000 -5.773759 0.000000
.....................
(up to the remainder of the 60 atoms)
K_POINTS automatic
26 26 1 0 0 0
CELL_PARAMETERS hexagonal
24.527679 0.000000 0.000000
0.000003 6.614491 0.000000
0.000000 0.000000 10.000000
_________________________________________________________________
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