9753227 Parks This project seeks new knowledge and understanding of materials that are at the forefront of condensed matter physics research through the use of terahertz spectroscopy. Materials of interest include, for example, a new compound recently discovered that contains clusters of twelve manganese atoms with a total spin of 10. Quantum tunneling of the spin was observed, and because the spin-split levels are separated by energies of 1.2 THz, terahertz spectroscopy is well suited to characterizing these levels. Capability for doing this spectroscopy at temperatures well below the measurement frequency is important for studying other systems as well, such as vibrational modes of semiconductor nanocrystals, quasiparticle scattering rates in high temperature superconductors, and Drude peaks in materials with extremely high electronic effective masses. %%% This is a research enhancement grant made under the Professional Opportunities for Women in Research and Education (POWRE) program. The research will contribute basic materials science knowledge at a fundamental level. An important feature of the program is the integration of research and education through undergraduate student participation in research. ***