The benefits of high resolution spectroscopy in the VUV

(Received 30 October 1991, accepted 21 January 1992)

Abstract
Recent experiments in high resolution laser-based spectroscopy extending into the VUV are described. Several motivations are discussed - in particular, the study of many-body effects and interchannel interactions. The phenomenon of autoionisation, especially when resonances overlap with each other and interact, is singled out, because it provides examples of several novel effects whose occurrence has only been established through high resolution experiments. The theory of these effects is outlined and several examples are given. The techniques involved in the data acquisition involve both thermionic diode detection and magneto-optical rotation as well as photoabsorption experiments.