Resonant vibrational excitation of the c3Πustate in HD and D2by electron impact

Metastable excitation cross section measurements are presented for the first time for deuterium hydride and deuterium. Narrow resonance features observed in the 11-13 eV energy range are compared with the previously observed resonance features in molecular hydrogen. A time-of-flight technique is used to isolate and measure the metastable molecules from the other products of the collision and this has allowed the detection of the v =0,1,2,3,4 vibrational levels in the c 3 Π u state. The positions of the resonance features are calibrated on an absolute scale and compared with earlier studies.