[lammps-users] Force on atoms and energy output

Dear all

I do some calculate the tensile property of carbon nanotubes. I build a finite length tube, fix the atoms at one end and move a constant distance on the other end atoms then fix them. One thing I wish to get is the total force on nanotube using minimize command.

I use ‘fix setforce’ command to fix the end atoms, and want to get the force on the end atoms.

When I try to output the force on the end atoms using ‘dump fx fy fz’, I found the output forces are zero for the end atoms. Would you please let me know how I can get the resultant forces on the fixed atoms? Thanks.

Another question is about energy. In my atomistic model, the atom style is molecular, that means the total potential energy in my model includes bond energy, angle energy, dihedral energy, improper energy and others. I want to get the definite value of each kind energy in the final equilibrium configuration after minimization. Would you please tell me whether I can get them? Thanks.

Regards, Lu.

The fix stores the force on the set of fixed atoms before
it zeroes them. So extract those values from the fix. See
doc/Section_howto, 4.15


You can print any components of the total potential energy (pair, bond,
etc), by using the appropriate thermo keywords - see the thermo_style
custom command.