In less than one minute the catalytic activity and selectivity of a single catalyst was measured in combinatorial libraries of ternary Rh-Pd-Pt-Cu alloys. Only slightly more than two hours were needed to complete a library with 136 elements. The elements of the libraries (ca. 2-4 μg of material) are contained in a two-dimensional array synthesized by a thin-film technique. The analysis was performed by a scanning mass spectrometer (see picture).

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We describe a method of tracking wave packet trajectories by probing both the temporal and spatial evolution of a coherent state prepared by a femtosecond laser pulse in real time. Application to the NaI dissociation reaction illustrates this technique, in which the direction of wave packet propagation within the quasi-bound A 0 + potential is observed and correlated to the physical processes of extension and contraction of the Na-I bond. From the combination of spatial and temporal information observed from experiments, self-consistent potential energy functions for the A 0 + state and the higher-lying state accessed by the probe laser pulse are constructed. The dynamics and the validity of the potentials so derived are tested via semiclassical and quantum-dynamical simulations of the wave packet motion, and comparisons with potentials obtained from other methods are drawn.

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