HBCU Excellence in Research: Research and Education Center for Investigation of Chemical Transformations in Host-Guest Systems at Extreme Conditions

With support from the Chemical Structure, Dynamics, and Mechanisms-A (CSDM-A) program in the Division of Chemistry and the Office of Integrative Activities (OIA), Professor Mohammad Mahmood of Howard University and Dr. Alexander Goncharov of Carnegie Institution of Washington will use synchrotron and free electron laser X-ray diffraction, Raman, and optical spectroscopy to study host-guest compounds with a focus on C-N-O-H phase diagrams under extreme conditions of high pressures and temperatures. This work is intended to address the challenges associated with understanding the response of molecular materials and host-guest systems to the extreme conditions of high pressure and temperature and their chemical reactivity and transformations at these conditions. This research is a physical chemical study of relevance to earth, and planetary science as information about the structure, composition and stability of molecular and host-guest compounds can be used to address a variety of questions related to planetary interiors. Furthermore, this activity will open a possibility for the talented young scientists from underrepresented groups to be trained in an academic environment under combined supervision at Howard University and the Carnegie Institution to prepare them for potential careers in science. The proposed research program will be centered on investigations of matter under extreme conditions of high pressure and extreme temperatures (P-T). The focus will be on host-guest systems; both water cages hosts containing various guest molecules and co-crystalline systems will be studied. These systems are characterized by a wealth of physical and chemical phenomena, particularly under conditions of extreme temperature and pressure. This takes on additional relevance as some of these systems are thought to be components of planetary interiors. Professor Mahmood and Dr. Goncharov and their team including postdoctoral associates and graduate and undergraduate students will investigate the structure, composition and vibrational properties of these systems, as well as their physical and chemical transformations as a function of pressure and temperature. In so doing, the team aspires to establish potential connections of these systems with emergent phenomena such as high-temperature superconductivity. The experiments will involve state-of-the-art diffraction and spectroscopic techniques including synchrotron and XFEL diffraction, and Raman and optical spectroscopy performed with diamond anvil cells. As a result of these studies, it is anticipated that a better understanding of the chemistry and physics of host-guest complexes under extreme conditions will be developed. 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.