[AMBER] adQMMM overheating

From: Artur Przydacz <artur.przydacz.dokt.p.lodz.pl>
Date: Tue, 8 Aug 2017 23:03:40 +0200

Dear Amber Users,

I have a problem with adaptive QM/MM simulation. I have a quite simple
system, namely an amine solvated by water molecules I did minimisation, but
when I try to heat the system from 0K to 300K Amber doesn't stop at 300K
but keep heating it up untill the whole simulation crashes, which usually
happens at 600K using PM3 and at 400K using PM6. I am including the input
file and the groupfile, and if neccessary I will provide the output.

Input:
Heating
&cntrl
  imin = 0,
  irest = 0,
  ntx = 1,
  nstlim = 20000,
  dt = 0.001,
  ntb = 2,
  ntp = 1,
  taup = 1.0,
  cut = 8.0,
  !ntr = 0,
  ntc = 2,
  ntf = 2,
  tempi = 0,
  temp0 = 300.0,
  ntt = 6,
  gamma_ln = 5.0,
  ntpr = 50,
  ntwx = 1000,
  ntwr = 5000,
  ig=-1,
  ifqnt=1
/
&qmmm
  qmmask=':1',
  qmcharge=0,
  qm_theory='PM6',
  adjust_q=0,
  vsolv=2,
  qmshake = 0,
  qm_ewald = 1, qm_pme = 1,
  verbosity = 0,
/
&vsolv
  nearest_qm_solvent=8,
  qm_center_atom_id=1,
  verbosity = 1, debug = 0,
/
&adqmmm
  n_partition=6,
  verbosity=1,
  print_qm_coords=1,
  debug = 0, verbosity = 2,
/

Groupfile:
# groupfile for adaptive solvent QM/MM run with n_partition = 6
-O -i heat.mdin -c min-IV.rst -p box-IV.prmtop -suffix heat
-O -i heat.mdin -c min-IV.rst -p box-IV.prmtop -suffix heat
-O -i heat.mdin -c min-IV.rst -p box-IV.prmtop -suffix heat
-O -i heat.mdin -c min-IV.rst -p box-IV.prmtop -suffix heat
-O -i heat.mdin -c min-IV.rst -p box-IV.prmtop -suffix heat
-O -i heat.mdin -c min-IV.rst -p box-IV.prmtop -r heat-IV.rst -x
heat-IV.mdcrd

Best regards
Artur

-- 
Institute of Organic Chemistry
Lodz University of Technology, Faculty of Chemistry
┼╗eromskiego 116, 90-924 Lodz, Poland
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Received on Tue Aug 08 2017 - 14:30:02 PDT
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