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-vektor of collective density field
  • K = spring constant of bias potential
  • a = anchor point of bias potential

Examples

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]

Description

The fix applies a force to atoms given by the potential

_images/fix_rhok.jpg

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.

Restrictions

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