[gmx-users] OPLSAA parameters

[Elisabeth]

Hello to all,

I am looking for bonded and nonbonded parameters for C H atoms in saturated
hydrocarbons.

atom types are:
Carbon atoms opls_135      opls_136
H  opls_140

 opls_135   12.01100  ; alkane CH3
 opls_136   12.01100  ; alkane CH2
 opls_140    1.00800  ; alkane H.

Please help me out with the following:

- I am wondering if I am selecting the correct values, for C-C and C-H bonds
from ffoplsaabon.itp.

C     C       1    0.15100   292880.0   ; wlj oxalic acid, etc.
HC    C       1    0.10900   284512.0   ; wlj 7/96

- what does wlj mean?

- what are the units?


Angle

 CA     CA     CZ      1   120.000    585.760   ; wlj
  CA     CA     CR      1   120.000    527.184   ;
  CA     CA     CX      1   120.000    711.280   ;
 C      CT     Cl      1   109.800    577.392   ; wlj

- I can not distinguish CA CZ .... What are they referring to?

[ dihedraltypes ]

 C      C      CT     HC      3      0.17782   0.53346   0.00000  -0.71128
0.00000   0.00000 ; dicarbonyls BMC 8,1881(2000)

- Is this what I need for oplsaa 135 136 140?

ffoplsaanb.itp.

 opls_135   CT    6     12.01100    -0.180       A    3.50000e-01
2.76144e-01
 opls_136   CT    6     12.01100    -0.120       A    3.50000e-01
2.76144e-01

 opls_140   HC    1      1.00800     0.060       A    2.50000e-01
1.25520e-01

- are these parameters for

 opls_135   12.01100  ; alkane CH3
 opls_136   12.01100  ; alkane CH2
 opls_140    1.00800  ; alkane H.

?

Also in usr/local/gromacs/share/gromacs/top/ directory  I can not find
ffoplsaanb,itp and ffoplsaabon.itp for 4.5.4 whereas in previous versions
these files were accessible. I am using itp files from version 4.0.7 and
wanted to make sure the above parameters for oplsa_135 oplsa_136 and
oplsa_140 have been remained unchanged in 4.5.4. Where can I find these
files?

Thanks,
Regards,
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://maillist.sys.kth.se/pipermail/gromacs.org_gmx-users/attachments/20110730/cb1e09b9/attachment.html>