My research program is centered on ultrafast dynamics at soft interfaces using femtosecond nonlinear laser spectroscopies. I will develop a series of surface-specific nonlinear optical techniques to directly probe ultrafast dynamics and chemical reactions at interfaces. The program will combine the experiences from my graduate work on surface-specific spectroscopy (second order) and my postdoctoral research on 2D spectroscopy (third order) to develop surface-specific 2D spectroscopy (fourth order).
My research program will focus on two main directions: the dynamics of water in interfacial regions and in complex systems relevant to biological and atmospheric systems, and the study of fundamental interfacial electron transfer processes in nano-composite systems for alternative energy applications.
Dynamics of Water in Interfacial Environments and Complex Systems
It is hard to over-emphasize the significance of water in nature and biological systems. The importance of water for the stability and functionality of biological systems has long been recognized, but only recently has the influence of water on the dynamical properties of biological systems been investigated. Furthermore, recent studies have discovered distinct chemical reactions taking place on the surface of aqueous systems, such as aerosols, in atmospheric environments. Whereas the dynamics of bulk water have been studied extensively, the dynamics of interfacial water at both extended surfaces and in “solvent” shells around biological matter have only recently been investigated experimentally using indirect measurements. By developing the abovementioned ultrafast surface-specific 2D spectroscopic techniques, we will be able to directly probe the dynamics of water at interfaces and chemical reaction dynamics of surface specific reactions.
Interfacial Electron Transfer in Nano-composite Systems for Solar Energy Applications
In light of the world’s soaring energy consumption, coupled with the detrimental environmental consequences of burning fossil fuels, developing plentiful, affordable, clean, and renewable energy sources is perhaps the biggest challenge of the century. Solar energy is by far the most abundant alternative energy source. More solar energy hits the surface of the earth in an hour than is consumed worldwide in a year. Harvesting solar energy on a large scale that could compete with fossil fuels requires the development of cheap, efficient solar technologies. Alternative solar technologies often involve nano-composite systems including dye-synthesized surfaces and quantum dots (QDs) to capture the solar energy. However, the fundamental electron transfer mechanisms in such nano-composite systems are not well understood. Again the ultrafast surface-specific optical techniques will be of great benefit for obtaining a detailed molecular understanding of the interfacial electron transfer in such systems.
|
Petersen, P.B.; Roberts, S. T.; Ramasesha, K.; Nocera, D. G.; Tokmakoff, A. “Ultrafast N-H vibrational dynamics of cyclic doubly hydrogen-bonded homo- and heterodimers” J. Phys. Chem. B, 2008, 112, 13167-13171.
Petersen, P.B.; Saykally, R. J. “Is the Liquid Water Surface Basic or Acidic? Macroscopic vs. Molecular-Scale Investigations” Chem. Phys. Lett. , 2008, 458, 255-261.
Petersen, P.B.; Saykally, R. J. “On the Nature of Ions at the Liquid Water Surface” Ann. Rev. Phys. Chem., 2006, 57, 333-364.
Petersen, P.B.; Saykally, R. J. “Adsorption of Ions to the Surface of Dilute Electrolyte Solutions: The Jones-Ray Effect Revisited” J. Am. Chem. Soc., 2005, 127, 15446-15452.
|
