Hi, I am working on a very short QM/MM simulation and having some problems
to understand the temperature control. This is the input file I am using:
QM/MM Molecular Dynamics
&cntrl
nstlim=10000, dt=0.0005, imin=0, ntpr=2000, ntwx=2000, ntwr=2000,
tempi=300.0,temp0=300.0, ntt=1, tautp=2.0, ig=209858, irest=0, ntx=1,
ntc=1, ntf=1, cut=8.0, ntb=1,
ifqnt=1
/
&qmmm
qmmask='.13722-13777',
qmcharge=0,
qm_theory='dftb3',
qmshake=1,
qm_ewald=1, qm_pme=1
/
Coordinates are read from an energy minimization rst file, so I assigned
tempi=300.0 and temp0=300.0. Since the dynamics is very short, I was
expecting to have a constant temperature from the beginning.
It started at 299.40 K, but later temperatures were:
1 ps: 188.22K
2 ps: 212.79K
3 ps: 231.05K
and so on. Is this normal and I should give the simulation more time to
reach the 300K value, or am I doing something wrong?
Thanks!
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Received on Mon Oct 30 2017 - 22:00:03 PDT
