The quantum world of cold electron collisions

Collisions between electrons and molecules at thermal energy play a key rol e in the chemistry and physics of plasmas, ranging from those in space to t he chemically active plasmas used for thin film and microcircuit fabricatio n. However, until recently, data for electron-molecule interactions below a few hundred millielectronvolts impact energy (a few thousand kelvin) were very sparse. Our experiments, using a high-resolution synchrotron photoioni zation source of electrons, have opened up this low-energy field. We presen t recent results which reveal some of the striking quantum scattering event s which take place as long-wavelength, low-energy electrons encounter molec ules, choosing H-2, N-2, benzene, halobenzenes, methanol, ozone, and chlori ne dioxide as examples.