He tagged C60+ in front of an image of the sky. Laser spectroscopy of such weakly bound complexes enables the determination of absorption lines of cold cations and anion from the UV to the IR upon single photon absorption. These spectra are then compared with observational data obtained by ground and space based telescopes.
Currently, more than 200 molecules have been identified in the interstellar medium. In addition, astronomers have recorded some 600+ absorption bands in diffuse interstellar clouds where UV light is expected to ionize heavy elements and most molecules. Utilizing He tags as messengers for photoabsorption, it is possible to determine electronic transitions of cold molecular ions and clusters and compare them with absorption lines recorded by modern astronomical telescopes, both ground and space based.