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# fix rheo/oxidation command

## Syntax

    fix ID group-ID rheo/oxidation cut btype rsurf

- ID, group-ID are documented in fix command

- rheo/oxidation = style name of this fix command

- cut = maximum bond length (distance units)

- btype = type of bonds created

- rsurf = distance from surface to create bonds (distance units)

## Examples

    fix 1 all rheo/oxidation 1.5 2 0.0
    fix 1 all rheo/oxidation 1.0 1 2.0

## Description

Added in version 29Aug2024.

This fix dynamically creates bonds on the surface of fluids to represent physical processes such as oxidation. It is intended for use with bond style bond rheo/shell.

Every timestep, particles check neighbors within a distance of cut. This distance must be smaller than the kernel length defined in fix rheo. Bonds of type btype are created between a fluid particle and either a fluid or solid neighbor. The fluid particles must also be on the fluid surface, or within a distance of rsurf from the surface. This process is further described in (Clemmer).

If used in conjunction with solid bodies, such as those generated by the react option of fix rheo/thermal, it is recommended to use a hybrid bond style with different bond types for solid and oxide bonds.

## Restart, fix_modify, output, run start/stop, minimize info

No information about this fix is written to binary restart files. None of the fix_modify options are relevant to this fix. No global or per-atom quantities are stored by this fix for access by various output commands. No parameter of this fix can be used with the start/stop keywords of the run command. This fix is not invoked during energy minimization.

## Restrictions

This fix must be used with the bond style rheo/shell and fix rheo with surface detection enabled.

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

## Related commands

fix rheo, bond rheo/shell, compute rheo/property/atom

## Default

none

(Clemmer) Clemmer, Pierce, O’Connor, Nevins, Jones, Lechman, Tencer, Appl. Math. Model., 130, 310-326 (2024).