RIKEN Atomic Physics Lab Seminar


"VUV Spectroscopy of rare gas dimers --Ion core transfer in high Rydberg states"

Y. Fukuda (University of Tokyo)

4:00 p.m.-, Monday, May 1st

Meeting Room 624-626 at 6th Floor, RIKEN Main Building.

"Electron Interactions with Excited Atoms and Molecules"

Loucas G. Christophorou

National Institute of Standards and Technology, U.S.A.

2:00 p.m.-, Thursday, May 25

Meeting Room 624-626 at 6th Floor, RIKEN Main Building


This lecture will highlight recent advances on electron interactions with excited atoms and molecules showing in a quantitative manner that the interactions of slow electrons with atoms and molecules are not only a function of the electron kinetic energy, but also of the INTERNAL energy of the target atom or molecule. As a rule, the cross sections for electron scattering from - and ionization of - excited atoms far exceed the respective cross sections for ground-state atoms. The larger polarizabilities of the atomic excited states compared with the respective ground states largely account for the higher electron scattering cross sections from excited atoms and also for other significant differences between the scattering cross sections of ground-state and excited atoms such as the absence of the Ramsauer-Townsend minimum in the electron scattering cross sections of the excited heavier rare gases. Similarly, the cross sections for electron scattering from excited molecules are much larger compared to the respective ground states.

Additionally, substantial measurements on dissociative and non- dissociative electron attachment to RO-VIBRATIONALLY excited molecules demonstrate the role of the total internal energy of the excited molecule on the dissociation cross section in the case of dissociative electron attachment, while recent experimental results on electronically excited molecules show that the cross sections for dissociative electron attachment to ELECTRONICALLY excited molecules can be orders of magnitude larger than for the ground-state molecules. It will be indicated that the field of electron interactions with excited atoms and especially with excited molecules is wide open and full of basic challenges and potential for applications.