Infrared photodissociation spectroscopy
Infrared photodissociation (IRPD) spectroscopy uses infrared radiation to break bonds in, often ionic, molecules (photodissociation), within a mass spectrometer. In combination with post-ionization, this technique can also be used for neutral species.
Source: Wikipedia — Infrared photodissociation spectroscopy (CC BY-SA 4.0)