VASP

vasp_Si

Liquid Si - Standard MD

POSCAR

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Si cubic diamond conventional cell
  5.43100000000000
 1.00000000 0.00000000 0.00000000
 0.00000000 1.00000000 0.00000000
 0.00000000 0.00000000 1.00000000
  Si
  8
Direct
  0.00000000 0.00000000 0.00000000
  0.75000000 0.25000000 0.75000000
  0.00000000 0.50000000 0.50000000
  0.75000000 0.75000000 0.25000000
  0.50000000 0.00000000 0.50000000
  0.25000000 0.25000000 0.25000000
  0.50000000 0.50000000 0.00000000
  0.25000000 0.75000000 0.75000000

KPOINTS

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K-Points
 0
Gamma
 1  1  1
 0  0  0

INCAR

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ISMEAR = 0
IBRION = 0
MDALGO = 2
ISIF = 2
SMASS = 1.0
SIGMA = 0.1
LREAL = Auto
ALGO = VeryFast
PREC = Low
ISYM = 0
TEBEG = 2000
NSW = 50
POTIM = 3.0
NCORE = 2
  • To select a molecular dynamics calculation set IBRION=0.
  • By selecting MDALGO=2 and ISIF=2 we select the NVT ensemble using the Nose-Hoover thermostat.
  • The tag SMASS specifies the Nose mass, which is a ficitional mass for the fictional coordinate of the heat bath. The choice of SMASS=1.0 should work well for this tutorial.
  • Since we are dealing with a super cell, we set LREAL=Auto. In this mode the projection operators are evaluated in real space. This should speed up the calculation while being slightly less accurate then the evaluation of the operators in reciprocal space.
  • To significantly speed up the calculations we use ALGO=VeryFast and PREC=Low. This is ok for this tutorial example but for more precise results these flags should be used with caution!
  • A time step of 3 femtoseconds (POTIM=3.0) is employed in this example, which should be ok for many applications of Si.
  • The tag NCORE=2 specifies that the parallelization is done such that 2 cores share the work on one orbital. This means that for e.g. 8 cores 4 different orbitals would be treated simultaneously, where for each orbital two plane-wave coefficients would be calculated simultaneously.

POTCAR