Energy selective excision of CN- following electron attachment to hexafluoroacetone azine ((CF3)2C=N-N=C(CF3)2)

Low energy electron attachment (DEA) to hexafluoroacetone azine (HFAA) leads to a remarkable energy selective excision of CN- within a pronounced resonance located at 1.35 eV. The underlying dissociative electron attachment ( DEA) reaction involves multiple bond cleavages and rearrangement within the neutral products. A series of further fragment ions (F-, CF3-, (CF3)(2)C- and (CF3)(2)CN-) are observed from resonant features above 2 eV and only (CF3)(2)CN- is additionally formed within a narrow resonance below 1 eV. In contrast to CN- all the remaining fragment ions can be formed by simple bond cleavages with (CF3)(2)CN- being the result of a symmetric decomposition of the target molecule by cleavage of the (N-N) bond with the excess charge localised on either of the identical fragments. Our ab initio calculations predict an adiabatic electron affinity of HFAA close to 2 eV with the geometry of the relaxed anion considerably distorted with respect to that of the neutral molecule.