General Physics Colloquium

Speaker:

James M. Lisy
University of Illinois at Urbana-Champaign

Title:

Non-covalent interactions: Balancing enthalpy and entropy, enabling size-selectivity, and controlling dynamics

Abstract:

While the focus of chemistry in the 20th Century was on understanding the nature of the chemical bond, it has been argued that the challenge for the 21st Century will be understanding the nature of non-covalent interactions. With a range of strengths from very weak (van der Waals) through hydrogen bonds to strong ion-neutral electrostatic interactions, they pose a significant challenge to both experimentalists and theoreticians. In particular, the balance between these interactions, their ability to both compete and cooperate, governs the structure, stability and function of complex systems, such as proteins and DNA. However examples of all of these effects can easily be found in smaller systems, such as clusters of molecules, atoms and ions. This presentation will be an overview of experimental and supporting computational studies of gas-phase molecular clusters containing a single ion, where the size and composition of the cluster can be controlled at the molecular level, using mass spectrometric methods. Structural and dynamical information on these species are obtained from their infrared spectra.

Coffee and cake will be served at 15:05