I’m trying to do a 3D md NVE simulation but I keep getting the MDMAXTEMP error before the first timestep completes. I’ve tried reducing the timestep as low as .00001 ps and increasing the structure size, but still nothing has worked. I’m modeling the simulation after example15.gin that came with the gulp source code

Hi Yuval
I’m not sure from your post what temperature you are initially setting the velocities to, but as you are running an NVE simulation there won’t be a thermostat applied to control the temperature. This means it’s important to relax the structure before starting the MD otherwise you will potential dump all the excess potential energy into the kinetic energy & this may cause the temperature to explode. You should also check that the initial structure and force field you are using are reasonable for the problem.

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Is there a way to relax a structure using gulp?

Optimising structures and computing their properties via lattice dynamics is GULP’s main purpose rather than MD. Just look for the keyword “opti” in the examples, help text and manual.

will do. thanks for the help