Project

liquid micro-jet; electron spectroscopy; resonances; radiation damage

Lead
Lay summary
Electron impact experiments provide insight into structure of the molecular targets and properties of the temporary negative ion species. So far, all existing experiments have worked with target molecules in gas or solid phase. The scope of the present project is to do electron spectroscopy on liquid targets. Context and impact: Processes induced by free electrons play an important role in several scientific fields, e.g., radiation damage to biological tissue or atmospheric chemistry. Plethora of these processes in nature occurs in liquid environment. However, elementary electron-impact phenomena were generally experimentally studied only for the gas and solid phase targets. Due to a simple reason - experiments with free electrons require high vacuum environment. It is difficult to bring the surface of clean volatile liquid into such vacuum. Recently, this difficulty has been partially overcome by the invention of a liquid micro-jet technique at MPI Göttingen, Germany. To our knowledge, the present experiment will be the first to investigate electron scattering on liquid micro-jets. The experiment will provide the data about electron-induced molecular damage occurring in liquid phase. A research field that should benefit the most from this data is that of radiation damage to biological systems. It is a well known fact, that the majority of biological damage is caused not by the high-energy radiation itself but rather by secondary slow electrons which are created by this radiation. The present experiment may, for example, identify the intermediate - 'doorway' - states of such secondary electrons as they are slowed down in liquid. Methodology: The project consists from two parallel parts. In major part, the electron-driven processes at liquid interface will be investigated by the combination of the liquid micro-jet technique and the electron scattering infrastructure available in Fribourg. This implies construction of the liquid micro-jet source, its implementation on the electrostatic spectrometer and measurements of electron energy loss spectra for a range of liquids. Simultaneously to that, the principles governing electron-driven processes in single molecules will be characterized, by means of measuring the quantitative data - i.e., the electron scattering cross sections for various scattering channels.

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Last update: 21.02.2013

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This Ambizione research project aims towards understanding of the processes at liquid interfaces induced by free low-energy electrons. Electron-induced processes occurring in the liquid environment play an important role in several scientific fields, e.g., radiation damage to biological tissue or atmospheric chemistry. In contrary to the gas and solid phase targets which have been intensively studied in recent years, the processes occurring at collisions of free electrons with liquid phase targets are almost completely unknown. The reason for this - the difficulty in bringing the surface of clean volatile liquid into high vacuum environment - has been recently overcome by the invention of the liquid micro-jet technique at MPI Göttingen, Germany. We propose a combination of the liquid micro-jet technique with the unique electron spectroscopy infrastructure available at the Department of Chemistry, University of Fribourg, in order to fill this important gap in the field of electron-induced chemistry.