STIMULATED RAMAN PUMPING OF C-2(-) PROBED VIA RESONANT 2-PHOTON DETACHMENT

We demonstrate for the first time that stimulated Raman pumping (SRP) can be used to vibrationally excite gas-phase negative ions. Results are presented for C-2(-), in which stimulated Raman pumping excites a rotationally resolved transition between the upsilon = 0 and upsilon = 1 levels of the ground (2) Sigma(g)(+) state; this excitation is monitored by resonant two-photon detachment through the excited B 2 Sigma(u)(+) state. At least 35% conversion to the upsilon = 1 level was achieved in this study. It is expected that this method is quite generally applicable and will provide an excellent tool for the study of the vibrational spectroscopy of negative ions.