231 research outputs found
Resonant two-photon single ionization of two atoms
Resonant two-photon ionization in a system consisting of two spatially
well-separated atoms is studied. Due to two-center electron-electron
correlations, the ionization may also proceed through photo-excitation of both
atoms with subsequent interatomic Coulombic decay. We show that this channel
may dominate the photoionization process and qualitatively change its
dependence on the field intensity and the spectra of emitted electrons.Comment: 4 pages, 4 figure
Excitation of heavy hydrogen-like ions by light atoms in relativistic collisions with large momentum transfers
We present a theory for excitation of heavy hydrogen-like projectile-ions by
light target-atoms in collisions where the momentum transfers to the atom are
very large on the atomic scale. It is shown that in this process the electrons
and the nucleus of the atom behave as (quasi-) free particles with respect to
each other and that their motion is governed by the field of the nucleus of the
ion. The effect of this field on the atomic particles can be crucial for the
contribution to the excitation of the ion caused by the electrons of the atom.
Due to comparatively very large nuclear mass, however, this field can be
neglected in the calculation of the contribution to the excitation due to the
nucleus of the atom.Comment: 15 pages, 2 figure
Excitation of highly charged hydrogen-like ions by the impact of equivelocity electrons and protons: a comparative study
We consider excitation of highly charged hydrogen-like ions by the impact of
equivelocity electrons and protons. The kinetic energy of the protons is more
than three orders of magnitude larger than that of the equivelocity electrons.
It is shown, however, that despite this fact, the electrons can be much more
effective in inducing excitation at collision velocities (slightly) above the
threshold for electron impact excitation. The basic reason for this is the
strong distortion of the motion of the electron by the attractive field of the
nucleus of the highly charged ion.Comment: 5 pages, 5 figure
Relativistic electron-ion recombination in the presence of an intense laser field
Radiative recombination of a relativistic electron with a highly charged ion
in the presence of an intense laser field is considered. Various relativistic
effects, caused by the high energy of the incoming electron and its strong
coupling to the intense laser field, are found to clearly manifest themselves
in the spectra of the emitted -photons.Comment: 4 papes, 2 figure
Young-type interference in projectile-electron loss in energetic ion-molecule collisions
Under certain conditions an electron bound in a fast projectile-ion,
colliding with a molecule, interacts mainly with the nuclei and inner shell
electrons of atoms forming the molecule. Due to their compact localization in
space and distinct separation from each other these molecular centers play in
such collisions a role similar to that of optical slits in light scattering
leading to pronounced interference in the spectra of the electron emitted from
the projectile.Comment: 4 pages, 3 figure
Relativistic transfer ionization and the Breit interaction
We consider correlated transfer ionization in relativistic collisions between
a highly charged ion and a light atom. In this process two quasi-free electrons
of the atom interact with each other during the short collision time that
results in capture of one of them by the ion and emission of the other. We show
that this process is strongly influenced by the generalized Breit interaction
already at modest relativistic impact energies.Comment: 5 pages, 4 figure
Collectively enhanced resonant photoionization in a multi-atom ensemble
Photoionization of an atom via interatomic correlations to N neighboring
atoms may be strongly enhanced due to constructive interference of quantum
pathways. The ionization proceeds via resonant photoexcitation of a neighbor
atom and subsequent interatomic Coulombic decay. The enhancement can scale with
N^2, leading to "super-enhanced photoionization".Comment: 4 pages, 2 figure
Two-center resonant photo ionization
Photoionization of an atom , in the presence of a neighboring atom ,
can proceed via resonant excitation of with subsequent energy transfer to
through two-center electron-electron correlation. We demonstrate that this
two-center mechanism can strongly outperform direct photoionization at
nanometer internuclear distances and possesses characteristic features in its
time development and the spectrum of emitted electrons.Comment: 4 pages, 3 figure
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