The room is equipped with a Paul ion trap mass spectrometer (Esquire Bruker 3000+) which has been extensively modified to allow coupling with CLIO free electron laser, an OPO / OPA table laser, a CO2 laser and a UV laser. An ion mobility device ( DIMS type) is also available on this ion trap. This equipment allows the possibility to record IRMPD( IR Multiple Photon Dissociation Spectroscopy) or UV spectra of mass selected ions within the mass spectrometer. The ions are put in gas phase through an ESI source. Isomeric forms selection is possible thanks to differential ion mobility. The instrument trap has also been modified to introduce neutral molecules directly into the ion trap in order to produce ion-molecule reactions.