Percentage contribution to the total L _CII luminosity from each different ISM component. The vertical shaded region marks the duration of the second main encounter. [C II] originates mainly from the WNM component at a percentage of ∼58%. CNM contributes an approximately constant ∼18% at all times. A similar contribution (∼14%) arises from the ionized material. H II regions contribute in general a low percentage to the total emission (∼10%), although there are certain times where they are in an early dense evolutionary stage, thus dense, in which their contribution dominates all phases. Finally, the [C II] emission originating from molecular gas is always negligible.