John Z. Larese

Principal Investigator

Education

Ph.D. (Physics), Wesleyan, 1982

Research

Surface Structure and Dynamics

I have studied a wide range of physical and chemical phenomena that take place at solid surfaces. These investigations mainly focus on the structure and dynamics of small molecules adsorbed on the basal plane of graphite, magnesium oxide and boron nitride. The experiments we performed used an array of sophisticated experimental techniques like x-ray and neutron diffraction and inelastic neutron spectroscopy. These studies are fascinating to me because I can examine how the physics and chemistry that takes place in two dimensions (2D) differs from that in three dimensions (3D). In some cases it is possible to follow how the rules that govern the 2D phenomena evolve toward those we are most familiar with in 3D. These surface studies are relevant to a number of important technologies such as gas separation and storage, heterogeneous catalysis, lubrication and microelectronics. I'm particularly interested in how the physical and chemical properties of finely divided particles with well-defined surface morphology vary depending on the size of the particle. Our current research can be divided into two broad areas: the surface physics and chemistry of small molecular films on pure and doped metal oxide surfaces and the synthesis of pure and doped, mono-dispersed, metal oxide particles with novel chemical, magnetic, physical, electronic or mechanical properties from a few nanometers to microns in length.

Adsorption, Structure and Dynamics

These studies rely upon our ability to perform combined thermodynamic (adsorption isotherm) and X-ray/neutron diffraction and neutron spectroscopy to probe the surfaces of well-characterized particles under realistic or "real-world" conditions. This is especially important in our studies of chemically active systems (like SO₂ and H₂S adsorption) because the chemistry of such systems is performed under conditions that are technologically relevant. It is reasonable to assume that very different results when studies in ultrahigh vacuum are used to "model" real catalytic processes. We have for example elucidated the surface chemistry of SO₂ on MgO surfaces a technologically important process used in atmospheric pollution control and are presently extending these studies to systems of similar importance.

Synthesis of Novel Metal Oxides

We are also studying the physical, chemical and hydrodynamic principles that govern the production of metal oxide particles of controlled size and chemical composition using a novel process that Walter Kunnmann (Brookhaven National Laboratory, retired) and I have recently developed and received a US patent for. At UT/ORNL, we are currently investigating the production and control of nanometer sized whiskers and wires of semiconductors and insulators with interesting chemical optical and electronic properties. The long-range goal of these studies is to develop a sound scientific basis for the development of novel, advanced materials synthesis and control.

Publications

1. Neutron Investigations of Rotational Motions in Monolayer and Multilayer Films at the Interface of MgO and Graphite Surfaces. J.Z. Larese, T. Arnold, A. Barbour and L.R. Frazier, Langmuir 25, 4078-4083 (2009).
2. Direct Observation of H2 Binding to a Metal Oxide Surface. J. Larese, T. Arnold, L. Frazier, R. Hinde and A. Ramirez-Cuesta, Phys. Rev. Lett. 101, 165302 (2008).
3. Electronic Structure Investigation of Surface−Adsorbate and Adsorbate−Adsorbate Interactions in Multilayers of CH₄ on MgO(100). M.L. Drummond, B.G. Sumpter, W.A. Shelton and J.Z. Larese, The Journal of Physical Chemistry C 111, 966-976 (2007).
4. Neutron Scattering. J.Z. Larese in Applications of Physical Methods to Inorganic and Bioinorganic Chemistry, R.A. Scott and C.M. Lukehart, eds. (Wiley, 2007).
5. Structure of an n -butane monolayer adsorbed on magnesium oxide (100). T. Arnold, S. Chanaa, S.M. Clarke, R.E. Cook and J.Z. Larese, Phys. Rev. B 74, 085421 (2006).
6. Novel method for the generation of high density (pure and doped) magnesium vapors which bypass the liquidus phase. W. Kunnmann and J.Z. Larese, U.S. Patent No. 6,179,897 (granted January 30, 2001).