63rd Annual Gaseous Electronics Conference and 7th International Conference on Reactive Plasmas
Volume 55, Number 7
Monday–Friday, October 4–8, 2010;
Paris, France
Session SF2: Electron Collisions with Atoms and Ions
8:30 AM–10:00 AM,
Friday, October 8, 2010
Room: 262
Chair: Don Madison, Missouri University of Science and Technology
Abstract ID: BAPS.2010.GEC.SF2.1
Abstract: SF2.00001 : Electron-ion collisions: precision spectroscopy and plasma rate coefficients*
8:30 AM–9:00 AM
Preview Abstract
Abstract
Author:
Alfred Mueller
(Giessen University)
Charge-changing interactions of electrons with target ions A$^
{q+}$ are studied. Cross sections and rate coefficients are
measured and the resonant excitation of the ions is employed in
a new type of precision spectroscopy.
Using charged particles as targets implies a number of
advantages and special aspects that can be exploited in
experiments. Beams of charged particles can easily be analyzed
and selected with respect to the mass, the charge state and the
energy of the particles. Hence, a beam of charged particles can
provide a very well characterized pure target for collision and
spectroscopy experiments. The determination of target density
distributions is difficult but the use of energetic charged
particles also offers the potential of very accurate
measurements. Plasma environments, man-made or of natural
origin, often contain ions in high charge states. Understanding
plasma properties requires detailed and accurate knowledge of
energy-dependent electron-ion cross sections specified by the
charge state of the ions. Moreover, variation of the charge
states of the target ions provides access to measurements along
iso-electronic sequences in which the number of electrons in the
system is kept constant, while the atomic number Z and the charge
state q are varied. Along an iso-electronic sequence the relative
importance of electron-nucleus and electron-electron
interactions gradually changes, thus providing an opportunity
to experimentally disentangle their influence on the structure
and dynamics of the atomic system studied.
Collisional spectroscopy exploiting resonance phenomena in
electron-ion interactions provides an efficient new tool to test
the most advanced theoretical calculations of atomic energy
levels and their decay properties, to investigate the validity of
quantum electrodynamics in strong fields, to understand atomic
and molecular physics at the borderline to nuclear physics and to
gain insights into the influence of collective effects as well as
the response of a single atom on the properties of molecules or
atomic clusters under the gradual increase of the number of atoms
in the system. Electrons are especially fine probes for studying
properties of atomic systems. High resolution measurements are
possible due to the availability of very highly developed
instrumentation, the possibility to exploit kinematic advantages
and the selectivity of electron-ion interactions.
*Support by the German Ministry of Education and Research BMBF is gratefullly acknowledged.
To cite this abstract, use the following reference: http://meetings.aps.org/link/BAPS.2010.GEC.SF2.1