Deactivation processes of homogeneous Pd catalysts using in situ time resolved spectroscopic techniques

UV-Vis, combined with ED-XAFS shows, for the first time, the evolution of inactive Pd dimers and trimers, that are a possible first stage in the deactivation process of important palladium catalysed reactions, leading to larger palladium clusters and eventually palladium black.     

Bell's theorem without inequalities and without alignments

A proof of Bell's theorem without inequalities is presented which exhibits three remarkable properties: (a). reduced local states are immune to collective decoherence; (b). distant local setups do not need to be aligned, since the required perfect correlations are achieved for any local rotation of the local setups; (c). local measurements require only individual measurements on the qubits. Indeed, it is shown that this proof is essentially the only one which fulfills (a). (b). and (c).     

Accumulation of dwell times in light diffusion

We discuss various speeds of propagation that are relevant for the dynamics of classical waves in random media: phase velocity, group velocity and transport velocity. The transport velocity can be much smaller than the phase velocity due to the long dwelling of classical waves inside resonant scatterers. We show that the transport velocity of light can be obtained experimentally by study both transient and steady-state diffusion of light.     

Comment on the NMR lineshape in low-dimensional paramagnets

It will be demonstrated that the model used by some workers to describe the NMR lineshape in low-dimensional magnetic systems is of academic interest only. Furthermore, we will show that this model was not treated properly. The NMR lineshape in low-dimensional systems has a normal single-peaked structure.     

What is measured in a time-resolved stimulated Raman experiment?

We have performed four-beam time-resolved stimulated Raman measurements on liquid CS₂. To interpret our results we have applied the response formalism for the third-order polarization to such an experiment. It turns out that the measured quantity is proportional to (a convolution of) Abs[χ⁽³⁾(-ω_s, ω_s, ω_l, -ω_l)]. As a consequence in this four-beam e xperiment one picks up electronic contributions in contrast to a two-beam experiment where Im[χ⁽³⁾] is observed.