Dear,
I run the scf calculation for hexagonal BeO structure. And The c parameter was not optimized after calculation. I found this c parameter is differ from literature data. I added the optimization file code. Do you have any comment for this input file. Where could there be a mistake ?
&CONTROL
calculation = "vc-relax"
forc_conv_thr = 1.00000e-03
nstep = 100
prefix ="BeO_scf_cal"
verbosity ="high"
restart_mode = "from_scratch"
outdir = './outdir'
pseudo_dir = "C:/Users/LENOVO/Desktop/QE/deneme/BeO"
/
&SYSTEM
celldm(1) = 5.098
celldm(3) = 3.067
degauss = 0.01
ecutrho = 650.0
ecutwfc = 65.0
ibrav = 4
nat = 4
ntyp = 2
occupations = "smearing"
smearing = "gaussian"
/
&ELECTRONS
conv_thr = 1.00000e-8
electron_maxstep = 100
mixing_beta = 7.00000e-01
startingpot = "atomic"
startingwfc = "atomic+random"
/
&IONS
ion_dynamics = "bfgs"
/
&CELL
cell_dofree = "all"
cell_dynamics = "bfgs"
/
ATOMIC_SPECIES
Be 9.012 Be.pbe-n-rrkjus_psl.1.0.0.UPF
O 15.999 O.pbe-n-rrkjus_psl.1.0.0.UPF
ATOMIC_POSITIONS {crystal}
Be 0.0000 0.0000 0.0000
Be 0.3333 0.6666 0.5000
O 0.0000 0.0000 0.3780
O 0.3333 0.6666 0.8780
K_POINTS {automatic}
16 16 14 0 0 0
Do you have de .out file? When you say that the c-parameter differ from literature, is it the value optimized? Looking your input file, it's all ok.
Bruno Poti e Silva many thanks for your reply. Actually, i found a and c is agree with literature data after geometric optimization in the last calculation. But i put into these structure parameters in the VESTA. İ didnt true structure for hexagonal. Please find the output run file (final parameters). Maybe i have a mistake in VESTA progress. Can you comment about this
Final enthalpy = -70.7131696023 Ry
Begin final coordinates
new unit-cell volume = 188.15339 a.u.^3 ( 27.88146 Ang^3 )
density = 2.97917 g/cm^3
CELL_PARAMETERS (alat= 5.09848111)
1.003111212 0.000000000 0.000000000
-0.501555606 0.868740238 0.000000020
-0.000000000 0.000000038 1.629110625
ATOMIC_POSITIONS (crystal)
Be -0.000009491 -0.000018981 0.000047311
Be 0.333309509 0.666619018 0.500047377
O -0.000010172 -0.000020344 0.377952669
O 0.333310153 0.666620307 0.877952643
End final coordinates
Dear Merve,
I believe that you need use real symmetry of the crystal in your calculation. Maybe i didn’t understand your problem well.
If you can explain better, maybe i can help you.
Best regards.
Bruno Poti e Silva thank you for reply. I have the structure when i put the final positions in VESTA after geometric optimization. Please find the attachment. It is wrong, its not hexagonal structure.
Maybe the structure is not fully optimized during geometric optimization. I dont know. The optimization file seems be okey.
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