[CP2K:2545] Constraint warning with AMBER PDB file
marco.stenta
marco.... at gmail.com
Wed Jun 22 06:44:21 UTC 2011
Dear Teodoro,
I'm running QM/MM cp2k on a pretty big system.
I'm using amber topology so I need a way to SHAKE the water molecules
I understand I do it in the &MOTION section with something like that, using
molecule as, without a psf I cannot specify the molname
&CONSTRAINT
&G3X3
MOLECULE 31
DISTANCES 1.7958 1.7958 2.85444
ATOMS 1 2 3
EXCLUDE_QM
&END G3X3
&END CONSTRAINT
Here 31 is the molecule kind number of the fist water molecule as guessed
from the output of a tentative run with verbose output: I get the molecule
kind name is MOL30 and the molecule kind number is 31: is it right?
31. Molecule kind: MOL30 Number of
atoms: 3
Atom Atomic kind name
1 OW
2 HW
3 HW
The name was automatically generated: T
Number of molecules: 1
Molecule list: 31
Number of bonds: 3
The problem is that I have 47883 water molecules: do I have to repeat this
CONSTRAINT section (or the &G3X3 subsection ) 50 thousand time? the input
would be pretty big.
Is there a clever way to SHAKE water molecules in my case?
you write in your previous answer
MOLECULE 1..15
but from the manual I understand MOLECULE takes only one integer: what does
your line mean? can I specify for a range instead then for a single
molecule?
Is it possible to have the code recognizing a MOLNAME also when one uses an
amber topology?
I am forced to use amber topology as I did not find the ambertocharmm
converter (leap2fist ?) anymore and I have to shake water, of course.
More in general: what do you mean by "molecule"?
each residue of a protein is assigned to a "molecule": what is the meaning
of that?
TOPOLOGY > PARA_RES<http://cp2k.berlios.de/manual/CP2K_INPUT/FORCE_EVAL/SUBSYS/TOPOLOGY.html#list_PARA_RES>is set to TRUE
what if I set it to FALSE?
I get the term molecule has nothing to do with its chemical meaning, but my
protein part is composed by more than one sub-units: does that conflicts
with PARA_RES<http://cp2k.berlios.de/manual/CP2K_INPUT/FORCE_EVAL/SUBSYS/TOPOLOGY.html#list_PARA_RES>FALSE?
Then I get some strange molecules as well like
1. Molecule kind: _QM_MOL0 Number of atoms:
10657
this is not the QM part, nor the QM + link and I am lost
thanks for the help
m
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