- B.S. 1999, Colorado State University
- Ph.D. 2004, University of Wisconsin–Madison
- Postdoctoral Research Associate, 2004-2009, University of Southern California and Argonne National Laboratory
- National Science Foundation CAREER Award, 2012
- Kansas NSF EPSCoR First Award, 2011
Areas of Specialization
Physical chemistry, ultrafast spectroscopy, chemical reaction dynamics
The primary focus of our work is to better understand the reaction dynamics of molecules in solution. We use ultrafast spectroscopy to monitor chemical reactions on the time scale of atomic motion and look for new ways to probe the dynamics in order to learn more about the fundamental physical processes that govern chemistry.
For example, we are interested in the excited state dynamics of "molecular photoswitches" that will be used in the next generation of data storage. Reversible opening and closing of a 6-member ring at the heart of these photochromic (color-changing) molecules enables them to store information based on the different absorption and refraction properties of each state. From a fundamental standpoint, these color changing reactions are fascinating because they involve dynamics on several different potential energy surfaces. Non-adiabatic transitions, vibrational relaxation, and solvent-solute interactions all play a role as the system moves along the reaction coordinate. We examine each of these, and try to exploit what we learn to control the outcome of the reaction.
A second area of our research examines the fundamental interactions between reactive species and the solvent environment. Specifically, we seek to understand how these intermolecular interactions affect reactivity in the electronic ground and excited states of a system. Simple models provide a window on the complex interactions that are important in systems as diverse as biomolecular complexes and energy storage materials.
Complementing our work on the above systems, we also use synchrotron-based time-resolved x-ray spectroscopy to observe reactions on the picosecond timescale. X-ray techniques are uniquely suited for studying the nuclear (and electronic) structure of condensed phase systems. With the ongoing development of ultrafast techniques, time-resolved x-ray spectroscopy will become a critical new tool for exploring reaction dynamics.
E. Pontecorvo, C. Ferrante, C. G. Elles, and T. Scopigno, Spectrally tailored narrowband pulses for femtosecond stimulated Raman spectroscopy in the range 330-750 nm, Optics Express, 21, 6866 (2013).
C. L. Ward and C. G. Elles, Controlling the excited-state reaction dynamics of a photochromic molecular switch with sequential two-photon excitation, J. Phys. Chem. Lett., 3, 2995 (2012).
I. L. Zheldakov, J. M. Wasylenko, and C. G. Elles, Excited-state dynamics and efficient triplet formation in phenylthiophene compounds, Phys. Chem. Chem. Phys., 14, 6204 (2012).
C. G. Elles, C. A. Rivera, Y. Zhang, and S. E. Bradforth, Electronic structure of liquid water from polarization-dependent two-photon absorption spectroscopy, J. Chem. Phys., 130, 084501 (2009).
C. G. Elles, I. A. Shkrob, R. A. Crowell, D. A. Arms, and E. C. Landahl, Transient x-ray absorption spectroscopy of hydrated halogen atom, J. Chem. Phys., 128, 061102 (2008).
C. G. Elles, I. A. Shkrob, R. A. Crowell, and S. E. Bradforth, Excited state dynamics of liquid water: Insight from the dissociation reaction following two-photon excitation, J. Chem. Phys., 126, 164503 (2007).
C. G. Elles, A. E. Jailaubekov, R. A. Crowell, and S. E. Bradforth, Excitation-energy dependence of the mechanism for two-photon ionization of liquid H2O and D2O from 8.3 to 12.4 eV, J. Chem. Phys., 125, 044515 (2006).
C. G. Elles and F. F. Crim, Connecting chemical dynamics in gases and liquids, Annu. Rev. Phys. Chem., 57, 273 (2006).