initial velocity of molecule with AIMD thermostat
Moderators: Global Moderator, Moderator
-
- Newbie
- Posts: 5
- Joined: Tue Sep 01, 2015 9:03 pm
initial velocity of molecule with AIMD thermostat
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
-------------------------------------------------------------------------
-
- Global Moderator
- Posts: 1817
- Joined: Mon Nov 18, 2019 11:00 am
Re: initial velocity of molecule with AIMD thermostat
Hi,
We're sorry that we didn’t answer your question. This does not live up to the quality of support that we aim to provide. The team has since expanded. If we can still help with your problem, please ask again in a new post, linking to this one, and we will answer as quickly as possible.
Best wishes,
VASP