Syntax:

ion <species-id> <x0> <x1> <x2> [v <vx0> <vx1> <vx2>] <moveScale> [<constraint type>=HyperPlane|Linear|None|Planar <d0> <d1> <d2> [<group> [HyperPlane <d0> ...]]]

Description:

Add an atom of species <species-id> at coordinates (<x0>,<x1>,<x2>).

Optionally, for dynamics, specify ion velocity <v0>,<v1>,<v2> after keyword 'v'.

<moveScale> preconditions the motion of this ion (set 0 to hold fixed)

In addition, the ion may be constrained to a line or a plane with line direction or plane normal equal to (<d0>,<d1>,<d2>) in the coordinate system selected by command coords-type. Note that the constraints must be consistent with respect to symmetries (if enabled).

The HyperPlane constraint allows constraining collective motion of many ions by restricting their motion to a hyperplane with normal specified by (<d0>,<d1>,<d2>) for all ions specifying a hyperplane constraint. By default, all hyperplane-constrained ions are included in a single group; use optional <group> label to specify multiple hyper-planes. Multiple hyperplane constraints may also be added to each atom, but this requires an explicit group label for each hyperplane.

Note that when coords-type is lattice, the constraints are in covariant lattice coordinates (like direction indices) for line constraints, but contravariant coordinates (like plane indices) for plane constraints.

Properties:

Requires: coords-type ion-species latt-scale

Forbids: (None)

Allow multiple: yes

Default: (None)

Back to: Input file documentation or Index of commands