For his leadership in separations science and technology; for improving nuclear fuel recycling and waste removal; and for leading the development process that was instrumental in the cleanup of waste at the Savannah River Site.
For environmental-effects research related to energy technologies and their use, focusing on the impacts of climate and atmospheric changes on the physiology, growth, and biogeochemical cycles of North American forest ecosystems.
For pioneering research and development of new materials for advanced energy technologies, including materials for (a) the storage of nuclear waste, (b) the solid-state generation of electrical power directly from heat, and (c) the lossless transport of electricity.
Mook has conducted neutron scattering research on a broad spectrum of materials. He is best known for his pioneering research on the magnetic excitations of transition metal ferromagnets and the observation of itinerant electron effects in these materials.