Supplement for Ultrafast Dynamics of Energetic Additives in O2 Clusters

Abstract : Extensive theoretical and experimental studies of the photochemistry of energetic cluster ions and the dynamics of molecular reactions within size-selected clusters have been carried out over the past three years. Photodetachment, photoelectron spectroscopy and photodissociation spectroscopy have been utilized to determine the structure of transient species: Incoherent control of reaction products in a cluster ion containing 35 atoms has been demonstrated and, more importantly, it has been shown that such a large tightly coupled complex can maintain a very non-statistical, chemically significant amount of excitation for at least 10 Ps. This result sets the time scale for possible control strategies. A new method has been developed to follow reaction dynamics in real time, starting with negative ion photodetachment to produce in energetic neutral, followed by a multiphoton ionization with a delayed ultrafast probe pulse. Direct information about coherent motion of the solvent itself is obtained by following the absorption recovery as detected by specific two-photon products, since it is the instantaneous cage configurations that determine the product branching ratios at given pump-probe delays.