Dear All,
I have been trying to use the free energy calculation capability of QM/MM module wiht NWChem 6.3. I did google a lot before posting here.
I am mostly following the instructions here
http://nwchemgit.github.io/index.php/QMMM_Free_Energy
and here
http://nwchemgit.github.io/index.php/QMMM_FEP_Example
First, it seems that we should use "task qmmm dft fep" instead of "task qmmm fep" shown in the example. The latter will results in "task: no task input for theory?" error.
Second, even with "task qmmm dft fep", I got following error
**********
* 0: Error opening topology file 2
**********
0:0::: 2
forrtl: error (76): Abort trap signal
One may suspect something is wrong with my topology file.
However, the same topology file has been used for optimizing the two configurations successfully. Can anyone give me some suggestions?
Where can I find a complete example (with all required files given) for running FEP with NWchem? There is no such test file in the QA directory.
Thanks a lot!
following is my input file. I have top file as BB.top, restart file as BB_path.rst
start BB
md
system BB_path
noshake solute
isotherm
end
qmmm
print low
nsamples 1000
ncycles 2
end
set qmmm:fep_geom BB_path-s.xyzi BB_path-e.xyzi
set qmmm:fep_esp BB_path-s.esp BB_path-e.esp
set qmmm:fep_lambda 0.0 0.1
set qmmm:fep_deriv .true.
task qmmm dft fep
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