Dear Users,
I am using amber 14 with Orca as external interface for QM/MM calculation.
I want to perform distance scanning using external interface. I am using
following script:
#####################################
QM-MM OPT using QM potential
&cntrl
imin=1, maxcyc=14,
ntb=1,ntmin =3,
ntf=1, ntc=2,drms=1.0E-2,
cut=8.0, ntwr=-1, ntpr=1,
ifqnt=1,
/
&lmod
lbfgs_memory_depth =5,
xmin_verbosity=2,
/
&qmmm
qmmask='.6094,7050-7054,7079-7118,7163',
qmcharge=0,
qm_theory='EXTERN',
spin = 2,
qmcut=8.0,
writepdb = 1,
qm_ewald = 0,
&orc
method = 'b3lyp',
basis = '6-31g*',
num_threads = 16,
maxcore = 4096,
maxiter = 9999,
convkey = 'LOOSESCF',
/
ncsu_smd
output_file = 'smd.txt'
output_freq = 1
variable
type = LCOD ! Linear Combination of Distances
i = (7081,7163,7117,7163)
r = (1.0,-1.0)
path = (1.41,-1.41)
harm = (1000.0)
end variable
end ncsu_smd
##############################
But unfortunately it doesn't write the smd.txt during optimization steps.
However similar script was working fine with DFTB method. Is something
wrong with above input or we cannot perform distance scanning with external
interface? Another problem with this interface is that it do not print
output energy for QM region in each steps but writes for total system
(QM+MM)therefore I am unable to get the change in energy of QM parts during
scanning. However, it writes the orca output but overwrites in next cycle
therefore I am unable to extract information form that too.
Since I have no expertise of changing code, I cannot modify the
qmmm_orca code to get desired output.
I will be very grateful if someone helps me to preform the qm-mm scan
and to get the free energy using external interface in Amber.
Thanks in advance
Kshatresh
--
With best regards
************************************************************************************************
Kshatresh Dutta Dubey
Post Doctoral Researcher,
Lise Meitner Center for Computational Quantum Chemistry
Hebrew University of Jerusalem Israel
Jerusalem, Israel
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Received on Sat Jan 31 2015 - 12:30:02 PST
