fix rhok command

fix ID group-ID rhok nx ny nz K a
  • ID, group-ID are documented in fix command

  • nx, ny, nz = k-vector of collective density field

  • K = spring constant of bias potential

  • a = anchor point of bias potential


fix bias all rhok 16 0 0 4.0 16.0
fix 1 all npt temp 0.8 0.8 4.0 z 2.2 2.2 8.0
# output of 4 values from fix rhok: U_bias rho_k_RE  rho_k_IM  |rho_k|
thermo_style custom step temp pzz lz f_bias f_bias[1] f_bias[2] f_bias[3]


The fix applies a force to atoms given by the potential


as described in (Pedersen).

This field, which biases configurations with long-range order, can be used to study crystal-liquid interfaces and determine melting temperatures (Pedersen).

An example of using the interface pinning method is located in the examples/USER/misc/rhok directory.


This fix is part of the USER-MISC package. It is only enabled if LAMMPS was built with that package. See the Build package doc page for more info.