For pioneering research in disturbance and landscape ecology and in modeling of land-use change with its implications for global changes, which have influenced environmental decision making on a worldwide scale.
For innovative and fundamental contributions to the understanding of the interactions and transport of electrons in gases and liquids, negative ion processes, the interfacing of the gaseous and condensed phases of matter, and the use of fundamental knowledge in the development of gaseous dielectrics, radiation detectors, and pulsed power
For fundamental studies in radiation physics, radiation dosimetry, and surface physics and for pioneering theoretical work on collective electron modes, surface electromagnetic waves in solids, and elucidation of the interaction of charged particles with matter.
For theoretical research on the electronic and vibronic structures and optical properties of defects in ionic crystals, and for work at the forefront of the rapidly developing field of laser annealing of semiconductors, leading to advances in the photovoltaic conversion of solar energy.
For original studies of the genetic effects of radiation in mammals. A world authority on mammalian mutagenesis, he and co-workers provided the experimental basis for estimating the genetic hazards of radiation to man and for the corresponding recommendations of national and international standards bodies