where P Q+ , with charge Q ≥ 0, is either a parent neutral molecule (Q = 0) or a (poly)cation (Q > 0), and X qX+ and Y qY+ are the daughter ions with charges q X ≥ 0 and q Y ≥ 0, respectively. The daughter ions' charges fulfill the charge conservation Q = q X + q Y . The following equation gives the dissociation energy of this reaction: