Energetics and dynamics through time-resolved measurements in mass spectrometry: Aromatic hydrocarbons, polycyclic aromatic hydrocarbons and fullerenes

Results of recent work on time-resolved photoionization and electron ionization mass spectrometry carried out in Jerusalem are reviewed. Time-resolved photoionization mass spectrometry in the vacuum ultraviolet is applied to polycyclic aromatic hydrocarbons, for example naphthalene, pyrene and fluoranthene as well as to some bromo derivatives (bromonaphthalene and bromoanthracene). Time-resolved photoionization efficiency curves are modelled by Rice-Ramsperger-Kassel-Marcus QET rate-energy k(E) dependences of the unimolecular dissociative processes and by the rate process infrared radiative relaxation k(rad). Experimental results are augmented by time-resolved photo-dissociation data for the same species, whenever available. Kinetic shifts, conventional and intrinsic (due to competition between dissociative and radiative decay), are evaluated. Activation parameters (activation energies and entropies) are deduced. Thermochemical information is obtained including bond energies and ionic heats of formation. Fullerenes, notably C-60, are studied by time-resolved electron ionization and a large intrinsic shift, due to competition with black-body-like radiative decay in the visible is discussed.