The Attachment subnode is available from the context menu (right-click the Collisions parent node) or from the Physics toolbar, Attributes menu. The Attachment subnode causes particles to become attached to background gas particles, removing them from the simulation. Optionally, the attached particle can then be released. Typically, the primary particles subjected to this collision type are electrons and the attached particle is a neutralized or ionized species from the background gas.

See Elastic for information about the Collision Statistics and New Value of Auxiliary Dependent Variables sections.

These settings are the same as for the Elastic subnode with an additional option to select the Release attached particle check box. When this check box is cleared, collisions only cause the primary particle velocity and auxiliary dependent variables to be reinitialized. When this check box is selected, a secondary particle is released during each collision.

This section is available when the Release attached particle check box is selected. Select an option from the Ion properties list, which can be any Particle Properties node that has been added to the physics interface. This controls the type of species that is introduced via secondary particle emission during the attachment reaction.

This section is available when the Release attached particle check box is selected. For each auxiliary dependent variable that is defined in the model, enter the initial value of the auxiliary dependent variable for the attached particle. The default value is 0.