Following early work on X-ray structure analysis, Dr. Morrison has engaged in work in the field of mass spectroscopy, in particular in its use in the study of ionization and excitation processes in molecular ions. Dr. Morrison is now an acknowledged leader in this field. His work, which has been characterized by ingenious experimental technique and original theoretical developments, has been largely responsible for the development of' electron-impact spectroscopy and through which information on the energy states of molecular ions can now be readily obtained. Because these states lie at energies which would place optical transitions to them in inaccessible regions of the far ultraviolet spectrum, almost no information was available until Morrison's recognition of the several distinct excitation processes possible in electron- or photon-molecule collisions allowed the establishment of energies and transition probabilities for both electronic and vibrational states of molecular ions. He has also made significant contributions to the use of high-resolution mass spectroscopy in the elucidation of molecular structure.
