Gary S. Collins
Scope of Research Interests:
Professor Gary S. Collins has a broad background in the application of nuclear methods to study the local structure of solids. Particularly through application of perturbed angular correlation spectroscopy (PAC), he and his group members have studied enthalpies of formation and migration of point defects such as vacancies (unoccupied lattice sites) and antisites (atoms on wrong sublattices) in metals and compounds. Interaction enthalpies between point defects have also been measured, as well as how site preferences of impurity atoms in compounds change as a function of composition and temperature. His group has also used PAC to study atomic diffusion at high temperature through measurement of nuclear relaxation at nuclei of probe atoms caused by fluctuating atomic environments. Measurement in thermal equilibrium at temperatures up to 1000 oC has been an essential feature of many of these studies. He has been recipient of $3.1M in grant awards from the Metals Program of the National Science Foundation, including eight single-investigator awards at WSU for the study of the local structure of metals and intermetallic compounds. He has mentored four postdoctoral associates, and eleven PhD, thirty MS, twenty-seven undergraduate, and three high-school students.
Professor Collins received a degree of BA in Physics from colonial Rutgers College, New Brunswick, NJ, in 1966. From then until 1968 he served as a Peace Corps Volunteer teaching math and science in French in secondary schools in Togo, West Africa. He entered graduate school in physics on his return to the US, receiving a PhD degree in Physics from Rutgers University in 1976 for research using Mossbauer spectroscopy under guidance of Professor Noemie Benczer-Koller. After staying on teaching for one more year at Rutgers, he took a postdoctoral position for two years at Clark University, in Worcester, MA, where he worked with Professor Chris Hohenemser. He continued a collaboration with Hohenemser for six more years at Clark as Research Assistant Professor. During that time, he was recipient as principal investigator of a two-year grant extension award from the National Science Foundation for “Outstanding Scientific/Technical Progress”, somewhat comparable to current “Career” grant awards. In 1985 he accepted a position at WSU in physics at the associate professor rank.
Current Research Interests:
Our methods are applicable to study interactions and properties of point defects in nearly all crystalline solids. Through measurement in thermal equilibrium at high temperature, one can determine interaction and migration enthalpies and, for solute atoms, site preferences, including enthalpies of transfer of a solute atom between two sites. Contact Collins to discuss the potential for studies of your interest. Below are outined two current areas of study in his group.
Interactions between solute atoms in compounds. What is the enthalpy of interaction between a pair of neighboring solute atoms dissolved in a compound? How does it depend on the host compound, the solutes, and the solutes they occupy? In a naive view, for example, each of the two solutes might be characterized by an effective charge equal to the difference in the nominal valence of the solute atom and the host atom it replaces. Collins’s group is carrying out experiments to directly measure interaction enthalpies, with hopes to develop heuristic rules to explain their systematics.
Diffusion of impurity atoms in compounds. In most crystalline solids, atomic motion (or diffusion) takes place through presence of “lattice vacancies”, or missing atoms, into which neighboring atoms can jump. But the diffusion is disturbed when the jumping atom is an impurity, both because the impurity may attract or repel a neighboring vacancy, and because jump rates of the vacancy in the neighborhood of the impurity will be modified. The overall effect is embodied in a “correlation coefficient for impurity diffusion” that has never been measured. For example, an impurity atom that has just jumped into a neighboring vacancy may have an enhanced or reduced probability of jumping back into the vacancy, relative to a host atom, thereby increasing or reducing the correlation coefficient. Experiments are underway to combine diffusivity and jump-frequency measurements to measure this coefficient for the first time.
Collins teaches at all levels. At the graduate level, he has taught Electricity and Magnetism 541 and 542, and, for many years, Statistical and Thermal Physics 533. He is currently teaching upper-division Thermal Physics 330 and introductory Physics for Scientists and Engineers I, Phys 201. He developed and taught the upper-division Quantum Physics Laboratory 415 for many years.
Within the university, Collins has been extensively involved with the Faculty Senate, including chairing major committees and running to be chair of the Senate. He represented the Physics Department as Senator for 12 years. He has chaired the department’s Graduate Studies Committee since 2012, which recruits new graduate students. Beyond the university, he has helped organize professional meetings, including a meeting of the Northwest Section of the American Physical Society (APS), held in Pullman/Moscow in 2004. He was named Outstanding Referee of the APS in 2011.