Dear all,
Paulatto gave me the new file for BFGS calculation. I have recompiled my QE and
finished the same calculation
for Anatase cell parameters. The results is my calculation can be finished
without stop at errors. But the parameters
is still smaller than literature both majority DFT calculation and experimental
data. The parameters are, a=3.7559
b=3.75561 c=9.3978, respectively.
My input file as follows,
&CONTROL
title = 'Anatase lattice' ,
calculation = 'vc-relax' ,
restart_mode = 'from_scratch' ,
outdir = '/home/vega/espresso-4.0/tmp/' ,
wfcdir = '/tmp/' ,
pseudo_dir = '/home/vega/espresso-4.0/pseudo/' ,
prefix = 'Anatase lattice default' ,
disk_io = 'none' ,
etot_conv_thr = 0.000000735 ,
forc_conv_thr = 0.0011668141375 ,
nstep = 1000 ,
/
&SYSTEM
ibrav = 6,
celldm(1) = 7.1469,
celldm(3) = 2.5124,
nat = 12,
ntyp = 2,
ecutwfc = 25 ,
ecutrho = 200 ,
/
&ELECTRONS
conv_thr = 7.3D-8 ,
/
&IONS
ion_dynamics = 'bfgs' ,
/
&CELL
cell_dynamics = 'bfgs' ,
/
ATOMIC_SPECIES
Ti 47.86700 Ti.pw91-sp-van_ak.UPF
O 15.99940 O.pw91-van_ak.UPF
ATOMIC_POSITIONS angstrom
Ti 0.000000000 0.000000000 0.000000000
Ti 1.888000000 1.888000000 4.743000000
Ti 0.000000000 1.888000000 2.372000000
Ti 1.888000000 0.000000000 7.115000000
O 0.000000000 0.000000000 1.973000000
O 1.888000000 1.888000000 6.716000000
O 0.000000000 1.888000000 4.345000000
O 1.888000000 0.000000000 9.088000000
O 1.888000000 0.000000000 5.141000000
O 0.000000000 1.888000000 0.398000000
O 1.888000000 1.888000000 2.770000000
O 0.000000000 0.000000000 7.513000000
K_POINTS automatic
4 4 2 1 1 1
I think there must be something wrong with my input file. Could you please do
me a
favor tell me what's wrong and why the cell parameters so small I'm thinking
about it
day and night.
By the way, I note that CASTEP has find 32 symmetry operations of my cell. My
cell is
a standard anatase crystall. But Q-E only can find 4 at most since I adjust
parameters of
~/espresso-4.0/PW/eqvect.f90. Do this matter effect my results significantly?
I'm look forwar for your advice.
Vega Lew
PH.D Candidate in Chemical Engineering
State Key Laboratory of Materials-oriented Chemical Engineering
College of Chemistry and Chemical Engineering
Nanjing University of Technology, 210009, Nanjing, Jiangsu, China
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