Experiments on free-free electron scattering, specifically the absorption or emission of 1.17 eV photons from a Nd:YAG laser field by an unbound electron when it is scattered by an atom or molecule, are reviewed. For large scattering angles such experiments are well described by a simple analytical theory that is independent of the properties of the target. At small scattering angles this theory breaks down for targets with a high dipole polarizability α, and an additional term needs to be incorporated in the scattering amplitude. This term is proportional to the dipole polarizability, and hence introduces the properties of the target into the free-free cross section - i.e., the laser field 'dresses' the atom. A progress report is given of free-free experiments designed to look for such 'dressed atom' effects during the electron-impact excitation of argon in the presence of a laser field; the lowest excited states of argon have α ≈ 300 atomic units.
|Journal||Journal of Physics B: Atomic, Molecular and Optical Physics|
|State||Published - Jun 5 2018|
Bibliographical noteFunding Information:
This work was supported by the United States National Science Foundation under GrantsNo.PHY-1607140 (NLSM), PHY-1402899 and PHY-1708108(BAdH). The authors would like to thank Dr David Atwood, of the Dept. Chemistry, University of Kentucky, for supplying the potassium charge, loading it into the oven, and demonstrating how safely to clean the potassium oxide from the vacuum chamber walls.
© 2018 IOP Publishing Ltd.
- electron scattering
- laser field
ASJC Scopus subject areas
- Atomic and Molecular Physics, and Optics
- Condensed Matter Physics