Dr Mathur has made experimental studies of low energy electronic and ionic collisions which explore the transformation of multi- particle collidants from one quantal state to another. For this purpose Dr Mathur has developed a state-of-the art energy spectrometric technique and various other related instrumentation in his laboratory. He has recently discovered a new class of isolated metastable multiply-charged molecular ions which dissociate much less rapidly than would be expected from the conventional perturbative single-particle theories of atomic collision.