On 4/27/2011 1:29 AM, Nilesh Dhumal wrote:
Hello,
I am trying to run a simulation for flexiable water. I use the parameters
from J. Chem. Phys. (2006),124,024503 paper and made floowing changes.
I addes "WAT" as a new residue name in aminoacids.dat
I addred two atom times in ffoplsaa.atp
opls_1001 15.99940 ; O SPC_fw Water
opls_1002 1.00800 ; H SPC_fw Water
I added following parameters in ffoplsaa.rtp
[ WAT]
[ atoms ]
OWA opls_1001 -0.82 1
HWA1 opls_1002 0.41 2
HWA2 opls_1002 0.41 2
[ bonds ]
OWA HWA1
OWA HWA2
I made a spc_fw.itp file.
; Derived from parsing of runfiles/alat.top.orig
[ defaults ]
; nbfunc comb-rule gen-pairs fudgeLJ fudgeQQ
;1 3 yes 0.5 0.5
; comb-rule 3 is square-root sigma, the OPLSAA version
This is a wrong approach. You should model your .itp file on the
existing standard water .itp files. They are designed so that you can
simply #include them in other topologies from the right places. Yours
cannot be used in this way, because you have erroneously used a
[defaults] directive (which can only appear once in a topology). You
should #include the main force field files, then #include a
properly-formed spc_fw.itp for the atom, bond and molecule types, then
specify your [molecules], as Justin said.
Mark
[ atomtypes ]
; full atom descriptions are available in ffoplsaa.atp
; name bond_type mass charge ptype sigma epsilon
opls_1001 OWA 8 15.99940 -0.820 A 3.1655e-01 6.503e-01
opls_1002 HWA 1 1.00800 0.410 A 0.00e+00 0.00e+00
[ bondtypes ]
; i j func b0 kb
OWA HWA 1 0.1012 443153.3808 ; J. Chem. Phys. (2006),124,024503
[ angletypes ]
; i j k func th0 cth
HWA OWA HWA 1 113.24 317.5656 ; J. Chem. Phys.
(2006),124,024503
[ moleculetype ]
; Name nrexcl
WAT 3
[ atoms ]
; nr type resnr residue atom cgnr charge mass typeB
chargeB massB
1 opls_1001 1 WAT OWA 1 -0.82
2 opls_1002 1 WAT HWA1 1 0.41
3 opls_1002 1 WAT HWA2 1 0.41
[ bonds ]
; i j funct
1 2 1
1 3 1
[ angles ]
; i j k funct
2 1 3 1
Finally I made changes in ffoplsaa.itp file
;#include "ffoplsaanb.itp"
;#include "ffoplsaabon.itp"
#include "spc_fw.itp"
#include "spc_fw_mol.itp"
For pdb2gmx
pdb2gmx -f water.pdb -o water.pdb -p water.top -ter
I get following error
Fatal error:
Atom OWA in residue HOH 1 not found in rtp entry with 3 atoms
while sorting atoms
WHy is reading HOH residue. In my pdb file I mentioned WAT as residure.
How can I fix this error?
Nilesh
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