Problem Obtaining Phonon Frequencies with VASP 5.2
Posted: Fri Mar 19, 2010 2:44 pm
Dear All:
I am having problems computing the phonon frequencies in VASP version 5.2 . The structure is converged with IBRION=2 but a run to obtain the phonons (IBRION=6) does not stop after energy convergence on wavefunction and then calculate the phonon frequencies. Any pointers would be useful. The INCAR and POSCAR files are below.
Trevor
*****************
INCAR
System=a-b-c, LDA+U, symm turned off, FM magnetic order
PREC= Accurate
ADDGRID = .TRUE.
Parallel Stuff
NPAR=8
ENCUT= 500.00 eV
ISPIN= 2 !spin polarized calculation
LORBIT=11
MAGMOM= 4 4 4 4 16*0 !make moment larger expected val.
ISTART=1
ICHARG=0
IBRION= 6 ! 2=conj grad and 1=quasi-Newton (variable metric) algorithm
NFREE=4
POTIM=0.015 !displacement of atoms in Ang.
LCHARG= .FALSE.
LWAVE= .FALSE.
LREAL=.FALSE. !needed for good convergence
ISYM=0 !switch Off symmetry (PAW potential)
IALGO= 38
EDIFF =1.0E-08
Ionic Relaxation (coarse for structural opt only)
NSW= 1
ISIF= 3 ! adjust abc xyz
EDIFFG= -5.0E-04 !5.0E-04 eV/A
************************
POSCAR
LDA+U, a, b, c, sy
1.000000000000000
5.2827497172433660 0.0000000000000000 0.0000000000000000
0.0000000000000000 5.8096041972536630 0.0000000000000000
0.0000000000000000 0.0000000000000000 7.5181314824947640
4 12 4
SELECTIVE DYNAMICS
Direct
0.5000000000000000 0.0000000000000000 0.0000000000000000 T T T
0.0000000000000000 0.5000000000000000 0.0000000000000000 T T T
0.0000000000000000 0.5000000000000000 0.5000000000000000 T T T
0.5000000000000000 0.0000000000000000 0.5000000000000000 T T T
0.1289637528571407 0.4505034259741735 0.2500000000000000 T T T
0.3710362471428598 0.9505034259741736 0.2500000000000000 T T T
0.6289637528571407 0.0494965740258261 0.7500000000000000 T T T
0.8710362471428594 0.5494965740258264 0.7500000000000000 T T T
0.6968524002712170 0.3255352627755137 0.0615065384729744 T T T
0.8031475997287830 0.8255352627755212 0.0615065384729744 T T T
0.1968524002712090 0.1744647372244789 0.5615065384729743 T T T
0.3031475997287906 0.6744647372244787 0.5615065384729743 T T T
0.3031475997287906 0.6744647372244787 0.9384934615270257 T T T
0.1968524002712090 0.1744647372244789 0.9384934615270257 T T T
0.8031475997287830 0.8255352627755212 0.4384934615270261 T T T
0.6968524002712170 0.3255352627755137 0.4384934615270261 T T T
0.9787805816886825 0.0823796520245213 0.2500000000000000 T T T
0.5212194183113175 0.5823796520245219 0.2500000000000000 T T T
0.4787805816886818 0.4176203479754792 0.7500000000000000 T T T
0.0212194183113179 0.9176203479754781 0.7500000000000000 T T T
I am having problems computing the phonon frequencies in VASP version 5.2 . The structure is converged with IBRION=2 but a run to obtain the phonons (IBRION=6) does not stop after energy convergence on wavefunction and then calculate the phonon frequencies. Any pointers would be useful. The INCAR and POSCAR files are below.
Trevor
*****************
INCAR
System=a-b-c, LDA+U, symm turned off, FM magnetic order
PREC= Accurate
ADDGRID = .TRUE.
Parallel Stuff
NPAR=8
ENCUT= 500.00 eV
ISPIN= 2 !spin polarized calculation
LORBIT=11
MAGMOM= 4 4 4 4 16*0 !make moment larger expected val.
ISTART=1
ICHARG=0
IBRION= 6 ! 2=conj grad and 1=quasi-Newton (variable metric) algorithm
NFREE=4
POTIM=0.015 !displacement of atoms in Ang.
LCHARG= .FALSE.
LWAVE= .FALSE.
LREAL=.FALSE. !needed for good convergence
ISYM=0 !switch Off symmetry (PAW potential)
IALGO= 38
EDIFF =1.0E-08
Ionic Relaxation (coarse for structural opt only)
NSW= 1
ISIF= 3 ! adjust abc xyz
EDIFFG= -5.0E-04 !5.0E-04 eV/A
************************
POSCAR
LDA+U, a, b, c, sy
1.000000000000000
5.2827497172433660 0.0000000000000000 0.0000000000000000
0.0000000000000000 5.8096041972536630 0.0000000000000000
0.0000000000000000 0.0000000000000000 7.5181314824947640
4 12 4
SELECTIVE DYNAMICS
Direct
0.5000000000000000 0.0000000000000000 0.0000000000000000 T T T
0.0000000000000000 0.5000000000000000 0.0000000000000000 T T T
0.0000000000000000 0.5000000000000000 0.5000000000000000 T T T
0.5000000000000000 0.0000000000000000 0.5000000000000000 T T T
0.1289637528571407 0.4505034259741735 0.2500000000000000 T T T
0.3710362471428598 0.9505034259741736 0.2500000000000000 T T T
0.6289637528571407 0.0494965740258261 0.7500000000000000 T T T
0.8710362471428594 0.5494965740258264 0.7500000000000000 T T T
0.6968524002712170 0.3255352627755137 0.0615065384729744 T T T
0.8031475997287830 0.8255352627755212 0.0615065384729744 T T T
0.1968524002712090 0.1744647372244789 0.5615065384729743 T T T
0.3031475997287906 0.6744647372244787 0.5615065384729743 T T T
0.3031475997287906 0.6744647372244787 0.9384934615270257 T T T
0.1968524002712090 0.1744647372244789 0.9384934615270257 T T T
0.8031475997287830 0.8255352627755212 0.4384934615270261 T T T
0.6968524002712170 0.3255352627755137 0.4384934615270261 T T T
0.9787805816886825 0.0823796520245213 0.2500000000000000 T T T
0.5212194183113175 0.5823796520245219 0.2500000000000000 T T T
0.4787805816886818 0.4176203479754792 0.7500000000000000 T T T
0.0212194183113179 0.9176203479754781 0.7500000000000000 T T T