With this award from the Major Research Instrumentation (MRI) Program, Professor Maria Buthelezi from Wheaton College and colleagues John Collins and Xuesheng Chen will acquire a pulsed laser/detection system with a tunable dye laser system, a detection system, and a cryogenic refrigerator system. The award will enhance research training and education at all levels, especially in the areas of (a) studies of host/guest interactions of photochromic molecules, and (b) luminescence properties of solid state materials.
A tunable laser is a laser whose wavelength of operation can be altered in a controlled manner. The dye laser uses an organic dye as the lasing medium giving a system that can be used over a broad range of wavelengths. Some of the dyes can be large molecules that emit light via fluorescence. The tunable dye laser/detection system will enable excited-state lifetime and time-resolved fluorescence measurements that are important to the investigation of several processes that occur in molecular complexes: radiative decay that leads to conformational states, non-linear energy transfer processes, and fluorescence quenching mechanisms. This instrumentation will also foster the interdisciplinary curricular and research interactions between chemistry, physics and biology at Wheaton College.
This MRI grant proposed to (1) purchase equipment relevant to the study of the excited states of complex molecules and (2) to implement the use of that equipment for research into the study of the optical properties of materials, for the training of undergraduate students in the techniques of optical spectroscopy, for expanding research programs into new areas, and for increasing collaborations both internal and external to the college. The goals of purchasing and setting up the equipment was met within the first year, and since then has been used in the fulfillment of the other goals. The research conducted by the students was in the following areas: the luminescence characteristics of materials for lighting applications, optical properties of molecules for optical switches and sensors, optical properties of nanoparticles, optical properties of silver nanostructured films for use in the sensing of harmful metals. Under the guidance of the PIs, approximately twenty undergraduate students were trained using the equipment. Of these students 75% were women and 25% were students of color. The student researchers were involved in all areas of the research process, including the following: synthesis of materials, optical characterization of materials, advanced spectroscopic techniques used to investigate specific characteristics for use in applications, the visualization and analysis of data, and the presentation of the results at scientific conferences. The research work was presented at a dozen scientific meetings, including local, national and international conferences. One group of students received the "second place poster" award at the 3rd Annual NanoWorcester symposium. Two senior honors theses also resulted from the work. Those students who have graduated have all entered, or plan to enter, STEM-related fields, such as Ph.D. programs in chemistry, medical school, and pathologistâ€™s assistant program. Those still in the pipeline plan to enter either similar STEM field, and those graduating this year are planning to enter fields such as medical school, engineering, and chemistry, with one other entering the industry in a startup making equipment for research. All students have received training in the Responsible Conduct for Research, and are well equipped to enter research facilities programs either in the graduate programs, industrial laboratories, or medical facilities. A set of interdisciplinary undergraduate teaching laboratories on the chemistry and physics of biological materials were developed and implemented in the physical chemistry course. Two of the PIs also established a new research collaboration with one another in the area of the optical properties of thin films. Other research avenues were also open, including one two with industries (General Electric and Osram Sylvania) in the area of the optical properties of semiconductor and insulating materials used in lighting. A collaboration with a theoretical physical chemist at the University of Massachusetts Dartmouth with expertise in electronic structure theory was initiated. Additionally, one international collaboration was also established with a research university in Lviv, Ukraine investigating the optical properties of silver thin films and nanostructured polymers for sensing applications. In summary, the quantity and the quality of the research in the physics and chemistry departments at Wheaton College has been raised significantly as a result of this grant, and we anticipate the continued growth in the use of these facilities.