4,941 research outputs found
Conserved Dynamics and Interface Roughening in Spontaneous Imbibition : A Critical Overview
Imbibition phenomena have been widely used experimentally and theoretically
to study the kinetic roughening of interfaces. We critically discuss the
existing experiments and some associated theoretical approaches on the scaling
properties of the imbibition front, with particular attention to the
conservation law associated to the fluid, to problems arising from the actual
structure of the embedding medium, and to external influences such as
evaporation and gravity. Our main conclusion is that the scaling of moving
interfaces includes many crossover phenomena, with competition between the
average capillary pressure gradient and its fluctuations setting the maximal
lengthscale for roughening. We discuss the physics of both pinned and moving
interfaces and the ability of the existing models to account for their
properties.Comment: 9 pages, Late
Stochastic dissociation of diatomic molecules
The fragmentation of diatomic molecules under a stochastic force is
investigated both classically and quantum mechanically, focussing on their
dissociation probabilities. It is found that the quantum system is more robust
than the classical one in the limit of a large number of kicks. The opposite
behavior emerges for a small number of kicks. Quantum and classical
dissociation probabilities do not coincide for any parameter combinations of
the force. This can be attributed to a scaling property in the classical system
which is broken quantum mechanically.Comment: 5 pages, 1 figure, accepted by J Chem Phy
Small rare gas clusters in soft X-ray pulses
We develop a microscopic model for the interaction of small rare gas clusters
with soft X-ray radiation. It is shown that, while the overall charging of the
clusters is rather low, unexpectedly high atomic charge states can arise due to
charge imbalances inside the cluster. The mechanism does not require unusually
high absorption rates, and the heating can be described by standard inverse
bremsstrahlung formulae.Comment: 4 pages, 4 figure
Triple photoionization of Lithium near threshold
Solving the full classical four-body Coulomb problem numerically using a
Wigner initial distribution we formulate a classical-quantum hybrid approach to
study triple ionization by single photon absorption from the Li ground state in
the threshold region.
We confirm the Wannier threshold law and we show
that the determined in the interval between 2-5 eV deviates from the
analytical threshold value of 2.16 which we find in the interval between
eV.Comment: 6 pages, 3 figure
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