Professor Bloomfield primarily researches clusters, small aggregates of atoms that fall in between atoms and solids. His group is particularly interested in two areas of cluster science: the study of magnetism in isolated metal clusters, and the study of electronic structure in insulator clusters. Their work on magnetism in metal clusters seeks to connect atomic and molecular magnetism with that of condensed matter. They find that reduced dimensionality and finite size effects tend to enhance the magnetism of small particles. Their studies of electronic structure in insulator clusters use femtosecond lasers to examine the molecular origins of crystalline structure, defects, and phase transitions in ionic and covalent solids. Prof. Bloomfield’s group has learned much about the accommodation of excess electrons in clusters and about the relationships between temperature and cluster structure.