Dr. W. Ariyasinghe engages in atomic and molecular physics experiments. The department has several electron beam facilities (2 eV to 10 KeV energy) for studying interactions of low energy and intermediate energy electrons with atoms and molecules. He utilizes these facilities to measure total electron scattering cross sections (TCS), the most reliable experimental scattering cross section, of atoms and molecules at low and intermediate energies. Accurate measurement in this region of energies requires extremely good energy and angular resolution to avoid effects due to forward-scattered electrons. With this in mind, he has developed an experimental station to produce accurate TCS measurements.
For the past few years he has been studying the TCS of chain-like hydrocarbons and fluorocarbons, research of great importance to astrophysics, atmospheric physics, chemical physics, plasma physics, bio-medical physics, and semiconductor physics. His goal in this area of research is to produce an accurate pool of TCS and to utilize those in the development of an empirical expression for the users in the above fields and in industry.
In addition to TCS related work, currently, he is in the process of developing an elecron source to study the vibrational overtone spectrum of molecules using energy-selective electron impact ionization.
Prior to working with electron beams, Dr. W. Ariyasinghe and collaborators have been involved with the study of
- molecular state effects of Auger emission under the bombardment of MeV ions,
- He+, H2+ and H+ ion induced K- shell and L-shell ionization cross sections of all second and third raw elements,
- isotropic/anisotropic nature of Auger emission, and (4) fragmentation of frozen hydrocarbons under MeV ion bombardment.