E-field on equilibrated system

Dear lammps users,

A system of polymer chains and lithium salt ions was equilibrated. (That is the system’s temperature and density was brought to 300k and 1.1g/cm3 respectively )

But once the electric field was applied along with a box size increase, the temp shot up to 60,000K.

If the box size is kept same so as to correspond to a density of 1.1, the temperature drops to 75K. But the electric field doesn’t show proper effects in this case. it is seen that the negative ions are also moving with the positive ones.

Please let me know if you have any ideas that could help. :slight_smile:

Two thoughts come to mind:
a) the steep temperature increase hints that your electric field may be far too strong
b) at the microscopic level the impact of a typical electric, like what is used in electrolysis or similar experiments, is only visible as a small net bias on the movement of particles of opposite charge. The macroscopic effect is on a much longer time scale than what is typically accessible to classical MD simulations. As a point of reference you could look up studies of conformation changes of voltage gated transmembrane proteins.

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