Dear all,
i'm having a strange problem with QM (/MM) system. I have 2 water
molecules that are, for now, QM and zero MM molecules. Later on I want
to change one of them to MM and add more water molecules that should be
QM/MM (adaptive). I'm using ORCA for the QM part of the calculation.
The problem is however, that the QM input coordinates are not being
updated - ORCA is working all the time with the original structure, but
Amber not. Do you please have got any suggestions where am i doing a
mistake?.
Thank you.
Sincerely,
stanislav.
my inputs (parameter file is attached):
Energy minimisation of fully QM Water Dimer
&cntrl
imin=1, ! Perform an energy minimization
ntx=1, ! Read coordinates but not velocities from inpcrd file
irest=0, ! Do not restart the simulation
ntpr=1, ! Logfile print frequency
ntwr=1, ! Restart file writing frequency
maxcyc=200, ! Maximum minimisation cycles
ntmin=0, ! For ncyc cycles steepest descent method is used then
conjugate gradient is switched on
ntc=1, ! SHAKE is not performed
jfastw=4, ! Do not use fast SHAKE routines for water
ntf=1, ! Complete interaction is calculated
ntb=0, ! No periodicity is applied and PME is off
cut=20.0, ! Nonbonded cutoff
igb=0, ! No generalized Born term is used
ifqnt=1, ! Include &qmmm namelist
/
&qmmm
qmmask=':1-2', ! Residues 1 and 2 are quantum
qm_theory='EXTERN', ! Use external programme for QM theory (orca)
scfconv=1.0d-8, ! Convergence criteria in kcal/mol
tight_p_conv=0, ! Loose convergence on the density matrix
vsolv=0, ! Do not include solvent molecules in QM region
adjust_q=0, ! No adjustment of charge is done
qmcharge=0, ! Total charge of qm atom list defined in
qmmask
spin=1, ! Multiplicity of the QM system
qmcut=20,
qm_ewald=0, ! Real-space cutoff for QM-QM and QM-MM longe
range interactions
qmmm_switch=0,
r_switch_hi=14,
r_switch_lo=12,
writepdb=1,
/
&orc
method = 'PBE',
basis = '3-21G',
use_template = 1,
/
###################################################################
orc_job.tpl:
# ORCA input file
%pal nprocs 1 end
!PBE 3-21G verytightscf
%BASIS GTOAUX=AutoBuild END
%method
grid 4
finalgrid 6
end
%scf
maxiter 100
end
%MaxCore 1024
! Angs NoUseSym
##################################################################
input structure:
default
6
1.9677787 3.3749857 1.8014289 1.1016907 2.8590060 1.819734
2
2.4542947 3.0348384 2.6339204 3.7215928 1.6446749 2.451509
9
3.2544504 2.0392279 1.6286084 4.6361695 2.0600117 2.426623
2
50.953000 50.356000 50.893000 90.0000000 90.0000000 90.000000
0
--
Stanislav Simko.
PhD applicant
Inorganic Chemistry and Catalysis
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Received on Fri May 20 2016 - 04:00:04 PDT
