compute ke/atom/eff command
compute ID group-ID ke/atom/eff
- ID, group-ID are documented in compute command
- ke/atom/eff = style name of this compute command
compute 1 all ke/atom/eff
Define a computation that calculates the per-atom translational (nuclei and electrons) and radial kinetic energy (electron only) in a group. The particles are assumed to be nuclei and electrons modeled with the electronic force field.
The kinetic energy for each nucleus is computed as 1/2 m v^2, where m corresponds to the corresponding nuclear mass, and the kinetic energy for each electron is computed as 1/2 (me v^2 + 3/4 me s^2), where me and v correspond to the mass and translational velocity of each electron, and s to its radial velocity, respectively.
There is a subtle difference between the quantity calculated by this compute and the kinetic energy calculated by the ke or etotal keyword used in thermodynamic output, as specified by the thermo_style command. For this compute, kinetic energy is “translational” plus electronic “radial” kinetic energy, calculated by the simple formula above. For thermodynamic output, the ke keyword infers kinetic energy from the temperature of the system with 1/2 Kb T of energy for each (nuclear-only) degree of freedom in eFF.
compute effTemp all temp/eff thermo_style custom step etotal pe ke temp press thermo_modify temp effTemp
The value of the kinetic energy will be 0.0 for atoms (nuclei or electrons) not in the specified compute group.
This compute calculates a scalar quantity for each atom, which can be accessed by any command that uses per-atom computes as input. See the Howto output doc page for an overview of LAMMPS output options.
The per-atom vector values will be in energy units.
This compute is part of the USER-EFF package. It is only enabled if LAMMPS was built with that package. See the Build package doc page for more info.