Sydney Leach

Sydney was always interested in diverse scientific areas and their interactions. His involvement in astrophysics led him to pursue the last part of his career at the Paris Observatory on its Meudon campus, in the Damap department, which has since become LERMA. Sydney, with Paul Felenbok, initiated the construction of the high-resolution 10m vacuum ultraviolet spectrograph, located in Meudon. His contributions to the study of the electronic spectra of molecules, and especially of radicals and molecular ions, are fundamental and very relevant today. He extended this field to dynamical aspects of larger species and undertook the study of fullerenes, amino acids and nucleic acids, as well as laboratory tests on the role of ions of polycyclic aromatic molecules in the interstellar medium. One of his latest projects on the international space station, EXPOSE, concerned the survival of plant seeds irradiated by UV radiation in space.