This grant supports the acquisition of a laser system to perform fundamental atomic physics research at Smith College. The research group is studying the complex interactions and inner workings of the atom. The best theoretical model of atomic systems is known as the Standard Model of Particle Physics. It is a very successful model, but we know it is not complete. For example, the Model does not include gravity or dark matter. Dark matter is a substance which astronomical observations indicate makes up 25% of the universe, but we know very little about. Two methods of improving our understanding of atomic systems are to work within the framework of the Model (known as testing the Model) or to work outside that framework (known as physics beyond the Standard Model). This laser system will enable this research group to use both methods in two independent projects. The first, which works within the Model, will perform experimental measurements on the light atoms beryllium, boron, nitrogen, and oxygen. Comparing these results to ongoing theoretical work from other groups will both test the validity of these complicated theoretical methods and, combined with the theoretical results, serve as a test of the Model. The second project, which works outside the Model, is to look for dark matter interaction with an isotope of holmium known as 166m-holmium. It is theorized that dark matter might cause an interaction with the nucleus that, if that interaction occurs, can be detected. The goal is to build a sensitive apparatus that will either detect this interaction or conclude this idea is not valid. In addition to this scientific impact, the Raven lab will continue to include a large number of undergraduate researchers through traditional lab projects and senior theses as well as our new course-based research experience (CURE). The goal of the CURE is to 1) provide a robust research experience for twelve undergraduate students each year and 2) train the next generation of scientists to perform high precision spectroscopy.<br/><br/>The Raven lab will use this new laser system to measure the absolute transition frequencies as well as hyperfine coupling constants, when applicable, of a variety of states in the light atoms to provide invaluable feedback to theorists who are in the pursuit of developing high precision multi-electron models. Combined with theoretical predictions, the results will serve to test the accuracy of quantum electrodynamics. Planned spectroscopic measurements will be performed on a number of triplet states in neutral beryllium-9, two transitions in the stable isotopes of boron, and a variety of states in nitrogen and oxygen. In addition, the Raven lab will develop an atom trap trace analysis (ATTA) apparatus for holmium atoms. 166-Ho is short lived while the metastable 166m-Ho state is long lived. Starting with a sample of only 166m-Ho atoms, ATTA will look for induced dark matter decay of 166m-Ho to the nuclear ground state. This new ATTA could also assist in the Electron Capture 163-Ho (ECHo) experiment, where 166m-Ho is a contaminant.<br/><br/>This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.