initial velocity of molecule with AIMD thermostat
Posted: Wed Sep 02, 2015 4:10 pm
Dear all,
I have a problem with inducing initial velocity of molecule under Nose-hoover thermostat while calculating AIMD (SMASS = 0 & MDALGO = 2).
What I want to calculate is that a molecule which has specific initial velocity (momentum) comes close to surface (supercell) which is controlled by Nose-hoover thermostat to maintain specific temperature. However, the initial velocity written in POSCAR file didn't work and just vibrating in the vacuum (also surface and lattice are vibrating). Actually when I used microcanonical ensemble (NVE, SMASS=-3) a molecule moves in the vacuum well, but I need to use canonical ensemble (NVT).
How can I induce the initial velocity of molecule in this situation?
Please help me.
Any comments are very thankful for me.
Thank you very much.
P.S. : I set My INCAR like below,
------------------------------------------------------------------------
general:
SYSTEM = h-BN_SC ! Title
ISTART = 0 ! 0 start from scratch, 1 use old WAVECAR
ICHARG = 2 ! 1 use old CHGCAR, 2 superposition atoms, +10 Fix CHG
ISMEAR = 0 ! -5 Tetra+Blochl, 0 Gaussian, >=1 MP
SIGMA = 0.05 ! Width smearing
! EDIFF = 1.0E-5 ! Electronic convergence criterium
PREC = Normal ! used precision
ALGO = Very Fast
LREAL = Auto
LWAVE = .FALSE. ! Write the WAVECAR file
LCHARG = .FALSE. ! Write the CHGCAR file
LVTOT = .FALSE. ! Do not write the potential file
! ENCUT = 850 ! Kinetic energy cutoff (ENMAX - B:318.614 & N:400)
dynamic (Ionic relaxation):
IBRION = 0 ! -1 fix atoms, 2 ConjGrad for relax
NSW = 1000 ! Number of ionic steps
! EDIFFG = 1.0E-4 ! Convergence criterium
NELMIN = 6 ! 8 RECOMMENDED
ISYM = 0 ! strongly recommened for MD
POTIM = 1.0 ! timestep 1 fs
SMASS = 0 ! NVT
MDALGO = 2 ! Nose-Hoover thermostat
TEBEG = 355 ; TEEND = 355 ! temperature
parallelisation:
LPLANE = .FALSE.
NPAR = 15
NSIM = 1
-------------------------------------------------------------------------
I have a problem with inducing initial velocity of molecule under Nose-hoover thermostat while calculating AIMD (SMASS = 0 & MDALGO = 2).
What I want to calculate is that a molecule which has specific initial velocity (momentum) comes close to surface (supercell) which is controlled by Nose-hoover thermostat to maintain specific temperature. However, the initial velocity written in POSCAR file didn't work and just vibrating in the vacuum (also surface and lattice are vibrating). Actually when I used microcanonical ensemble (NVE, SMASS=-3) a molecule moves in the vacuum well, but I need to use canonical ensemble (NVT).
How can I induce the initial velocity of molecule in this situation?
Please help me.
Any comments are very thankful for me.
Thank you very much.
P.S. : I set My INCAR like below,
------------------------------------------------------------------------
general:
SYSTEM = h-BN_SC ! Title
ISTART = 0 ! 0 start from scratch, 1 use old WAVECAR
ICHARG = 2 ! 1 use old CHGCAR, 2 superposition atoms, +10 Fix CHG
ISMEAR = 0 ! -5 Tetra+Blochl, 0 Gaussian, >=1 MP
SIGMA = 0.05 ! Width smearing
! EDIFF = 1.0E-5 ! Electronic convergence criterium
PREC = Normal ! used precision
ALGO = Very Fast
LREAL = Auto
LWAVE = .FALSE. ! Write the WAVECAR file
LCHARG = .FALSE. ! Write the CHGCAR file
LVTOT = .FALSE. ! Do not write the potential file
! ENCUT = 850 ! Kinetic energy cutoff (ENMAX - B:318.614 & N:400)
dynamic (Ionic relaxation):
IBRION = 0 ! -1 fix atoms, 2 ConjGrad for relax
NSW = 1000 ! Number of ionic steps
! EDIFFG = 1.0E-4 ! Convergence criterium
NELMIN = 6 ! 8 RECOMMENDED
ISYM = 0 ! strongly recommened for MD
POTIM = 1.0 ! timestep 1 fs
SMASS = 0 ! NVT
MDALGO = 2 ! Nose-Hoover thermostat
TEBEG = 355 ; TEEND = 355 ! temperature
parallelisation:
LPLANE = .FALSE.
NPAR = 15
NSIM = 1
-------------------------------------------------------------------------