Syntax:
deposition rate dirx diry dirz d0 lo hi
Examples:
deposition 1.0 0 -1 0 1.0 1 4 deposition 1.0 1 1 -1 1.0 3 10
Description:
This commands invokes deposition events in an on-lattice diffusion model, specified by the app_style diffusion command.
Deposition events will compete with diffusive hop events in the diffusion model. Each time a deposition event is selected, a random starting point at the top of the simulation box is selected (top y surface in 2d, top z surface in 3d). The atom trajectory is traced along its incident direction which is specified by (dirx,diry,dirz) and need not be a unit vector. However, diry < 0 and dirz = 0 is required for 2d models. Similarly, dirz < 0 is required for 3d models.
Candidate deposition sites are vacant sites within a perpendicular distance d0 from the incident trajectory which also have a current coordination number C such that lo <= C <= hi. Note that d0 is specified in distance units which will depend on how you setup your lattice via the app_style command. For example, if you specified you lattice constant or box size in Angstroms, then the distance units for this command are Angstroms as well.
If the inicident angle is not vertical, then periodic images of the starting point with associated incident trajectories are considered and the d0 capture distance is applied to whichever trajectory the candidate site is closest to, in a perpendicular sense. This means x-periodicity in 2d and x- and y-periodicity in 3d.
For the set of candidate sites, the selected deposition site is the one closest to the starting point, measuring a projected distance along the incident direction.
IMPORTANT NOTE: App_style diffusion defines valid sites as vacant (site value = 1) or occupied (value = 2). When performing deposition, a row (2d) or plane (3d) of sites at the top of the system (where the deposited atoms are incident from) should be set to a value of 3. This prevents those sites from being considered as candidate deposition sites, due to them being neighbors of occupied sites at the bottom of the system in a periodic sense.
Restrictions:
This command can only be used as part of the app_style diffusion application.
Deposition can currently only be done in serial simulations, not parallel. In serial, it can not be used with multiple sectors, only one sector.
Related commands:
Default: none