Thanks very much for your input, I could have never figured the error on my own since it doesn’t show up on either my console output or the logfile.
I guess this is because I was not using the latest version.
…and because you didn’t follow the LAMMPS manual about debugging crashes:
I am now using the latest stable release and I got the same error as you.
I have a follow-up question related to the error:
ERROR: Pair lj/long/dipole/long requires atom attributes mu, torque (src/DIPOLE/pair_lj_long_dipole_long.cpp:237)
I understand “mu” is the dipole that is associated with point particles.
How does one specify this for the extended rigid molecules?
mu and torque are properties of atoms and thus as enabled by using a suitable atom style.
For spheres, one can of course use:
set group group-ID dipole/random seed value
The error also mentions the “torque” for the atom attributes.
However, I do not see torque attribute for any of the atom styles or the molecules.
torque is not a static property that you set with the set command, but computed (like forces) during the computation of the interactions.
Albeit, the molecules do have the Moment of Inertia attribute that can be specified.
So, isn’t the “fix rigid/nvt/small” supposed to compute the torques internally based on the forces acting on the rigid particles/molecules?
I could not find anything relevant from the documentation, but it is very much possible I have missed it.
there is a difference between torque on rigid bodies and torque on atoms.
As regards the use of the options for the pair style “lj/long/dipole/long off off $$”, I had the same question.
The molecule actually has a linear quadrupole moment (i.e. two antiparallel dipoles).
which you are modeling through 4 point charges. so there is no need to include explicit dipoles and to use a pair style that uses such dipoles.
it looks to me that this is a file with errors.
a correct pair style would be lj/cut/coul/cut or any variant with a damped or long-range coulomb or lj variant, if needed.
However, I am merely trying to be consistent with the prescribed force-field given below that is taken from the MolMod database.
there are some items that look inconsistent:
the length of the time step. you have metal units to the unit of time is 1 picosecond and thus a timestep or 0.1ps is quite unrealistic.
the mass for the hydrogen atom seems to be missing
the time constant for the thermostat with 10ps is quite large
i’ve tried accessing this website, but since it doesn’t support https there are serious problems accessing it with an up-to-date webbrowser.