Two experiments, using a two-laser scheme, were carried out to identify specific structural isomers. For IR-IR hole burning experiments, the first laser was introduced such that the pulses intersected the ions in the cryogenic ion trap. The frequency of this laser was fixed at a transition unique to a specific isomer leading to the desorption of tags from just that isomer. The remaining tagged clusters, after a ToF separation, were probed by the second laser scanning the entire spectral region of interest much like the CIVP experiment described above. IR-IR double resonance spectra were collected by slightly modifying the above procedure. The first laser was scanned over the IR region of interest while the second laser was kept fixed at an infrared wavelength corresponding to a vibrational transition distinct to one specific isomer. The spectrum of each isomer was then obtained by monitoring the depletion of the ion signal.