Vacuum-UV chemical physics in the gas phase using synchrotron radiation

Charged particles travelling in a circle at velocities close to the speed of light have the fundamental property that they emit continuous electromagnetic radiation, widely called synchrotron radiation (SR). Initially discovered in the 1950s by high-energy physicists and regarded as a hindrance, SR is now used worldwide by physicists, chemists and biologists for fundamental and applied research. The physics of such sources is well understood. Briefly, the total energy emitted by a charged particle is proportional to z\(^2\)E\(^4\)/m\(^4\)R\(^2\), where R is the radius of curvature, and m, z and E are the mass, charge and energy of the charged particle, respectively. In most SR sources the electron is used for the charged particle, because it is easy to generate and has a high z/m ratio. Nearly all the experiments described here use the Daresbury SR source, run by the Council of the Central Laboratory of the Research Councils on behalf of the UK Government