Dr. KENNETH C. JANDA
Professor, Chemistry
School of Physical Sciences
A. B. 1973,, Hope College
Phone: (949) 824-5266 Fax: (949) 824-8571
Email: kcjanda@uci.edu
University of California
317C Rowland Hall
Mail Code: 2025
Irvine, CA 92697
Research Interests:
Chemical Physics, Gas Hydrate Clathrates, van der Waals Clusters
Academic Distinctions:
Sigma Xi Undergraduate Research AwardAppointments:
Research Abstract:
Determining the structure of a wide variety of molecules and relating structural information to chemical properties is one of the most important achievements of chemical physics. Progress along these lines requires close cooperation between theory and experiment. The theories that underlie interpretation of molecular spectra are now so well established that they are often taken for granted. The direct prediction of molecular structure by theory is also becoming part of the accepted arsenal of a chemist's tools. Our research has the joint goals of understanding the structural properties of ever more complicated chemical systems and achieving similarly powerful understanding of the underlying principles of chemical dynamics.
At present, we study several types of problems for which the role of experiments and theory are equally important for providing a fundamental understanding of the under lying processes. In one such study we are measuring how the electronic wave function of a molecule changes as it dissociates. For instance, for the A state of the ICl molecule we have recorded the electronic spectrum of ICl with sufficient resolution to determine the hyperfine constants for wide range of vibrational levels and this allows us to determine the configuration of the valence electrons as a function of the bond length. The results indicate that the LCAO-MO model presented in text books is not very useful for describing this state.
We have also determined the structures of a large number of complexes that involve one, two, or three noble gas atoms weakly bonded by van der Waals forces to a chlorine or a bromine molecule. High-resolution spectroscopy of these clusters reveals their geometrical structures, and pump-probe spectroscopy yields the lifetimes and dynamics of intramolecular vibrational energy transfer processes. Rigorous quantum mechanical analysis of the data reveals both the nature of the energy transfer mechanism within the complex and the kinematics of the dissociation.
Another system of interest is that of large helium clusters that contain up to 10,000 He atoms. Such clusters provide a unique medium for chemistry because evaporation holds the cluster temperature to about 0.5K. This allows otherwise extremely unstable species to coexist. We are learning how to deposit reactive species into the cluster and to use the cluster to deposit the reactive species onto a surface without inducing reaction.
Finally, we are studying a novel form of solids called gas hydrate clathrates. In these solids, water molecules form a hydrogen bonding network slightly higher in energy than pure ice, but whose structure consists of interconnected cages. The cages contain gas molecules such as chlorine, propane or methane, which the van der Waals reactions between the gas molecule and the cage are sufficient to stabilize the gas hydrate clathrate. In essence, the gas molecule is in a sub-nanoscopic vacuum chamber.
The Potential Energy Surface for the Interaction of a He Atom and a Cl2 Molecule
