Temperature in MD simulation

[kmkumar]

Dear All,

I started a MD with the following INCAR file.

-----------------------------------------------
SYSTEM = MD

Startparameter for this Run:
NWRITE = 2
LPETIM = F write-flag & timer
LWAVE = .FALSE
LCHARG = .TRUE
NPAR = 8
NSIM = 8
LPLANE = .TRUE

Electronic Relaxation 1
PREC = Low
ENMAX = 400.00 eV
ENCUT = 400.00 eV
NELM = 60
ALGO = Very_Fast
EDIFF = 1E-04 stopping-criterion for ELM
MAXMIX = 40
LREAL = auto

Ionic Relaxation
EDIFFG = -0.01 stopping-criterion for IOM
NSW = 2000 of steps for IOM
IBRION = 0 ionic relax: 0-MD 1-quasi-New 2-CG
ISIF = 0 stress and relaxation
ISYM = 0 0-nonsym 1-usesym
ISMEAR = 1
SIGMA = 0.1
ISPIN = 1
NUPDOWN = 1

NBLOCK = 1 ; KBLOCK = 100
NELMIN = 2
POTIM = 0.5 ! time-step for ion-motion (in fs)
SMASS = 0.4 ! Nose mass-parameter (am)
TEBEG = 300 ! temperature
--------------------------

According to this file, i set the Temperature of my simulation to be at 300K. But in the output file, i see that the temperature is drastically reduced which shows about almost 10 times smaller.

Also the calculation is very slow compared to the geometry relaxation steps.
Could some one help me where i am going wrong.

----------------------------
1 T= 4. E= -.19350695E+04 F= -.19351701E+04 E0= -.19351607E+04 EK= 0.11800E+00 SP= -.26E+01 SK= 0.25E+01
2 T= 4. E= -.19350696E+04 F= -.19351739E+04 E0= -.19351645E+04 EK= 0.12472E+00 SP= -.28E+01 SK= 0.28E+01
3 T= 4. E= -.19350696E+04 F= -.19351775E+04 E0= -.19351681E+04 EK= 0.13139E+00 SP= -.30E+01 SK= 0.30E+01
4 T= 4. E= -.19350697E+04 F= -.19351807E+04 E0= -.19351713E+04 EK= 0.13804E+00 SP= -.33E+01 SK= 0.33E+01
5 T= 4. E= -.19350698E+04 F= -.19351837E+04 E0= -.19351743E+04 EK= 0.14480E+00 SP= -.35E+01 SK= 0.35E+01
6 T= 5. E= -.19350698E+04 F= -.19351864E+04 E0= -.19351770E+04 EK= 0.15162E+00 SP= -.38E+01 SK= 0.38E+01
7 T= 5. E= -.19350698E+04 F= -.19351889E+04 E0= -.19351795E+04 EK= 0.15852E+00 SP= -.41E+01 SK= 0.41E+01
8 T= 5. E= -.19350700E+04 F= -.19351913E+04 E0= -.19351819E+04 EK= 0.16563E+00 SP= -.44E+01 SK= 0.44E+01
9 T= 5. E= -.19350699E+04 F= -.19351934E+04 E0= -.19351840E+04 EK= 0.17309E+00 SP= -.47E+01 SK= 0.46E+01
10 T= 6. E= -.19350700E+04 F= -.19351958E+04 E0= -.19351864E+04 EK= 0.18106E+00 SP= -.50E+01 SK= 0.50E+01
11 T= 6. E= -.19350700E+04 F= -.19351984E+04 E0= -.19351890E+04 EK= 0.18966E+00 SP= -.53E+01 SK= 0.53E+01
12 T= 6. E= -.19350701E+04 F= -.19352011E+04 E0= -.19351917E+04 EK= 0.19889E+00 SP= -.57E+01 SK= 0.56E+01
13 T= 6. E= -.19350701E+04 F= -.19352037E+04 E0= -.19351942E+04 EK= 0.20858E+00 SP= -.60E+01 SK= 0.59E+01
14 T= 7. E= -.19350701E+04 F= -.19352063E+04 E0= -.19351969E+04 EK= 0.21882E+00 SP= -.64E+01 SK= 0.63E+01
15 T= 7. E= -.19350702E+04 F= -.19352090E+04 E0= -.19351996E+04 EK= 0.22976E+00 SP= -.67E+01 SK= 0.66E+01
16 T= 7. E= -.19350703E+04 F= -.19352118E+04 E0= -.19352024E+04 EK= 0.24123E+00 SP= -.71E+01 SK= 0.70E+01
17 T= 8. E= -.19350703E+04 F= -.19352141E+04 E0= -.19352047E+04 EK= 0.25314E+00 SP= -.75E+01 SK= 0.74E+01
18 T= 8. E= -.19350703E+04 F= -.19352161E+04 E0= -.19352067E+04 EK= 0.26546E+00 SP= -.79E+01 SK= 0.77E+01
19 T= 8. E= -.19350702E+04 F= -.19352179E+04 E0= -.19352085E+04 EK= 0.27837E+00 SP= -.83E+01 SK= 0.81E+01
20 T= 9. E= -.19350703E+04 F= -.19352198E+04 E0= -.19352104E+04 EK= 0.29212E+00 SP= -.87E+01 SK= 0.85E+01
21 T= 9. E= -.19350703E+04 F= -.19352214E+04 E0= -.19352120E+04 EK= 0.30654E+00 SP= -.91E+01 SK= 0.89E+01
22 T= 10. E= -.19350703E+04 F= -.19352228E+04 E0= -.19352134E+04 EK= 0.32163E+00 SP= -.95E+01 SK= 0.94E+01
23 T= 10. E= -.19350702E+04 F= -.19352239E+04 E0= -.19352146E+04 EK= 0.33758E+00 SP= -.10E+02 SK= 0.98E+01
24 T= 11. E= -.19350702E+04 F= -.19352250E+04 E0= -.19352156E+04 EK= 0.35441E+00 SP= -.10E+02 SK= 0.10E+02
25 T= 11. E= -.19350701E+04 F= -.19352256E+04 E0= -.19352162E+04 EK= 0.37206E+00 SP= -.11E+02 SK= 0.11E+02
26 T= 12. E= -.19350702E+04 F= -.19352260E+04 E0= -.19352166E+04 EK= 0.39045E+00 SP= -.11E+02 SK= 0.11E+02
27 T= 12. E= -.19350702E+04 F= -.19352257E+04 E0= -.19352163E+04 EK= 0.40956E+00 SP= -.12E+02 SK= 0.12E+02
28 T= 13. E= -.19350699E+04 F= -.19352245E+04 E0= -.19352152E+04 EK= 0.42945E+00 SP= -.12E+02 SK= 0.12E+02
29 T= 14. E= -.19350699E+04 F= -.19352233E+04 E0= -.19352140E+04 EK= 0.45045E+00 SP= -.13E+02 SK= 0.13E+02
30 T= 14. E= -.19350698E+04 F= -.19352217E+04 E0= -.19352124E+04 EK= 0.47271E+00 SP= -.13E+02 SK= 0.13E+02
31 T= 15. E= -.19350698E+04 F= -.19352197E+04 E0= -.19352105E+04 EK= 0.49617E+00 SP= -.14E+02 SK= 0.14E+02
32 T= 16. E= -.19350697E+04 F= -.19352171E+04 E0= -.19352079E+04 EK= 0.52080E+00 SP= -.14E+02 SK= 0.14E+02
33 T= 17. E= -.19350696E+04 F= -.19352139E+04 E0= -.19352048E+04 EK= 0.54665E+00 SP= -.15E+02 SK= 0.15E+02
34 T= 17. E= -.19350697E+04 F= -.19352104E+04 E0= -.19352013E+04 EK= 0.57413E+00 SP= -.15E+02 SK= 0.15E+02
35 T= 18. E= -.19350695E+04 F= -.19352066E+04 E0= -.19351976E+04 EK= 0.60367E+00 SP= -.16E+02 SK= 0.16E+02
36 T= 19. E= -.19350696E+04 F= -.19352028E+04 E0= -.19351940E+04 EK= 0.63530E+00 SP= -.17E+02 SK= 0.16E+02
37 T= 20. E= -.19350694E+04 F= -.19351985E+04 E0= -.19351897E+04 EK= 0.66914E+00 SP= -.17E+02 SK= 0.17E+02
38 T= 21. E= -.19350693E+04 F= -.19351939E+04 E0= -.19351853E+04 EK= 0.70530E+00 SP= -.18E+02 SK= 0.17E+02
39 T= 23. E= -.19350692E+04 F= -.19351882E+04 E0= -.19351798E+04 EK= 0.74328E+00 SP= -.18E+02 SK= 0.18E+02
40 T= 24. E= -.19350691E+04 F= -.19351816E+04 E0= -.19351735E+04 EK= 0.78339E+00 SP= -.19E+02 SK= 0.18E+02
41 T= 25. E= -.19350689E+04 F= -.19351743E+04 E0= -.19351664E+04 EK= 0.82623E+00 SP= -.20E+02 SK= 0.19E+02
42 T= 27. E= -.19350689E+04 F= -.19351663E+04 E0= -.19351587E+04 EK= 0.87173E+00 SP= -.20E+02 SK= 0.19E+02
43 T= 28. E= -.19350688E+04 F= -.19351568E+04 E0= -.19351495E+04 EK= 0.91963E+00 SP= -.21E+02 SK= 0.20E+02
44 T= 30. E= -.19350687E+04 F= -.19351459E+04 E0= -.19351390E+04 EK= 0.97012E+00 SP= -.21E+02 SK= 0.21E+02
45 T= 31. E= -.19350685E+04 F= -.19351337E+04 E0= -.19351272E+04 EK= 0.10238E+01 SP= -.22E+02 SK= 0.21E+02
46 T= 33. E= -.19350686E+04 F= -.19351208E+04 E0= -.19351146E+04 EK= 0.10810E+01 SP= -.23E+02 SK= 0.22E+02
47 T= 35. E= -.19350683E+04 F= -.19351065E+04 E0= -.19351006E+04 EK= 0.11423E+01 SP= -.23E+02 SK= 0.22E+02
-------------------

[pkroll]

Wel, how does your POSCAR look like?
All velocities initially set to zero? In this case, the output you see is almost) what you can expect.
Try the following: after the positions in POSCAR, erase all the rest.
In your INCAR, set TINIT=300 ; TEBEG=300 and TEND=300 (you can play with these values according to your liking). Then choose a SMASS ....
This should work