[gmx-users] Alkane in water system simulation - TraPPE force field - Error: "Incorrect number of atomtypes for dihedral (4 instead of 2 and 4)"

[Shantanu Singh]

Hello!

Ignore the last mail.

So I am doing my B.Tech thesis on studying the diffusion coefficients of
alkanes at infinite dilution in water.
I am using TraPPE-UA model for alkanes and TIP4P/2005 representation for
water solvent. The problem is pretty simple but the simulations don't seem
to run.
I am currently working on ethane (C2H4).

When I try to run grompp for EM, I get the following error message -
*“Incorrect
number of atomtypes for dihedral (4 instead of 2 or 4)”. *
I figured there was something wrong with the topology file but nothing
seems out of place.


This is the link to the detailed error report and all other required files
for simulation:
*https://drive.google.com/file/d/0Bzfyv7uF7S2peGtOUEI0SExSdkU/view?usp=sharing
<https://drive.google.com/file/d/0Bzfyv7uF7S2peGtOUEI0SExSdkU/view?usp=sharing>*


The command line I am using is :

grompp -f minim.mdp -c ethane.gro -p ethane.top -o em.tpr


It would be great if you could find the time to have a look at it and help
me out.


Thank you

-- 
Regards

Shantanu Singh
Senior Undergraduate
IIT Delhi