Infrared multiphoton dissociation
Infrared multiple photon dissociation (IRMPD) is a technique used in mass spectrometry to fragment molecules in the gas phase usually for structural analysis of the original (parent) molecule. == How it works == An infrared laser is directed through a window into the vacuum of the mass spectrometer where the ions are.
Source: Wikipedia — Infrared multiphoton dissociation (CC BY-SA 4.0)