Contributed by Walter D. Loveland (D.W. Demoin edited)

Nuclear chemistry is generally defined as

• The study of the structure, reactions, and decay of nuclei;
• The study of macroscopic phenomena or technologies, such as nucleosynthesis or nuclear power, where nuclear phenomena are intimately involved; and
• The use of nuclear techniques to study microscopic phenomena, such as the chemistry of the heaviest elements an the diagnosis of disease.

More concisely, nuclear chemistry is what nuclear chemists do—and that encompasses a wide range of science. An integral component of nuclear chemistry is radiochemistry, the use of radioactivity to study chemical phenomena. Over recent decades, the efforts of nuclear chemists and nuclear physicists to understand the fundamental properties of nuclei have converged into a unified field—nuclear science.

Research Focus Areas

Some of the current topics in nuclear science today are:

• In the study of the structure of nuclei, many of the observed regularities are understood in terms of phenomenological models of collective and individual particle behavior. At small distances (and high energies), the quark and gluon fields are manifested. Current emphasis is on making and understanding measurements of nuclei at the limits of their existence. This frontier involves the study of the heaviest nuclei, barely held together against the repulsion of their electric charges, nuclei at high excitation energies, rapidly rotating nuclei, and nuclei with neutron-to-proton ratios that are very different from those of stable nuclei. Radioactive ion beams have opened up this latter area of study.
• The study of nuclear dynamics has focused on probing the response of nuclear systems to various modes of excitation. At lower energies, the time scales of nuclear decay by particle emission and fission have been probed. At higher energies, when the excitation energy per particle is of the order of the binding energy, measurements have focused on evidence for the existence of a nuclear liquid-gas phase transition. At relativistic energies, much effort is devoted to the observation of a phase transition between hot hadronic matter and a quark-gluon plasma. In the U.S., major research facilities like FRIB, RHIC, and Thomas Jefferson National Accelerator Facility have been built to facilitate these studies. The proposed Electron-Ion Collider (EIC) would further the experimental capabilities of these sites. Additionally, investment in theory-based tools (like high-performance computing) as well as experimental investment in detector and accelerator R&D help to fast-track discoveries.
• Nuclear analytical techniques are essential tools in the analytical chemist’s arsenal, with expanding applications in growing fields such as nuclear forensics. Successful use of these methods relies on both technical expertise and a clear understanding of the method’s limitations. Among these, the most widely employed radioanalytical method is radioimmunoassay (RIA)—a highly sensitive technique for quantifying trace amounts of antigens, hormones, and pharmaceuticals in biological systems.
• Understanding the chemistry of the transactinide elements have occurred through imaginative one-atom-at-a-time chemistry. Because of the complexity of the electron configurations of the actinide elements, the low levels of these elements in the environment, and the complexity of the chemical environment, progress in our understanding of the environmental behavior of the actinide elements has been slow but steady.
• Many nuclear chemists are focused on storage, remediation, and disposal options for the nuclear products generated by the nuclear power and defense industries.
• Perhaps no use of nuclear chemistry has greater human and monetary value than in applications in the field of nuclear medicine. Of special importance are the applications in diagnostic imaging and therapy where both chemistry of the radionuclide and its nuclear properties play important roles. Understanding the underlying biological systems as well as discovering unique biological vectors continue to change the landscape of what advances radiochemists and molecular biologists are making in the diagnosis and treatment of diseases.
• Emerging areas of radiochemical AI and automation, targeted alpha therapy (TAT), and many more continue to occupy the regions of research nuclear and radiochemists study.