195 research outputs found
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
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
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
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
Inelastic collisions of relativistic electrons with atomic targets assisted by a laser field
We consider inelastic collisions between relativistic electrons and atomic
targets assisted by a low-frequency laser field in the case when this field is
still much weaker than the typical internal fields in the target. Concentrating
on target transitions we show that they can be substantially affected by the
presence of the laser field. This may occur either via strong modifications in
the motion of the relativistic electrons caused by the electron-laser
interaction or via the Compton effect when the incident electrons convert laser
photon(s) into photons with frequencies equal to target transition frequencies.Comment: 4 pages, 2 figure
Relativistic time dilatation and the spectrum of electrons emitted by 33 TeV lead ions penetrating thin foils
We study the energy distribution of ultrarelativistic electrons produced when
a beam of 33 TeV Pb(1s) ions penetrates a thin Al foil. We show that,
because of a prominent role of the excitations of the ions inside the foil
which becomes possible due to the relativistic time dilatation, the width of
this distribution can be much narrower compared to the case when the ions
interact with rarefied gaseous targets. We also show that a very similar shape
of the energy distribution may arise when 33 TeV Pb ions penetrate a
thin Au foil. These results shed some light on the origin of the very narrow
electron energy distributions observed experimentally about a decade ago.Comment: Four pages, two 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
A new mechanism for electron transfer in fast ion-atomic collisions
We discuss a new mechanism for the electron capture in fast ion-atom
collisions. Similarly like in the radiative capture, where the electron
transfer occurs due to photon emission, within the mechanism under
consideration the electron capture takes place due to the emission of an
additional electron. This first order capture process leads to the so called
transfer-ionization and has a number of interesting features, in particular, in
the target frame it results in the electron emission mainly into the backward
semi-sphere.Comment: 4 pages, two figure
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