[gmx-users] Positive Total energy

[Thanasis Koukoulas]

Hello 
I have sent several emails and i am sorry. It is my last attempt to finish this simulation.The molecule i have is C-C-C-C-C-C-O-C-C-O-C-C-O-H or C10H1O3. (ciej molecule)
I dont use gromacs librariesthe files i use are attached to the email in which i have descriped step by step the forcefield i use. as you can see in [pairs] i have an extra non Lj 1-4 pair. i did it because the model i use has a potential between atom 10 and 14 ether oxygen and alchohol hydrogen interaction. It is described in the paper as a repulsive energy between these two atoms. and it has a formula:
Erepulsive = 3.325789e-7/r^12
the only way to import in gromacs i think is this:
[ pairs ]; ai aj funct 10 14    2 0 0 0 0 3.325789e-7
it is an intra-molecular only interaction. so i couldnt think another way to do it except this. as you can see i have several zeros for the charges, C6=o and C12 = 3.325789e-7 fidgeQQ=0 for this case
the problem is i get positive total energy. i did this sim for only one molecule just to see what is wrong and i think that coulomb (SR) are wrong for sure.
so i want 
coulomb 1-4 /2   !thats why i put fudgeQQ = 0.5
the values i get at the step 0 are
Energies (kJ/mol)          Angle    Proper Dih.          LJ-14     Coulomb-14        LJ (SR)    2.30340e+03    1.08417e+00    3.16570e+00    8.79204e+04   -2.54164e+03  Disper. corr.   Coulomb (SR)   Coul. recip.      Potential    Kinetic En.   -2.51250e+00   -4.81042e+04   -2.84931e+04    1.10867e+04    1.84852e+04   Total Energy    Temperature Pressure (bar)  Cons. rmsd ()    2.95719e+04    2.99528e+02   -3.03583e+02    3.13477e-06
tell me please how is this possible
thanks in advance and i am sorry once again


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