Vibrational Spectroscopy with Subnanometer Electron Beams: Correlating Chemistry and Atomic Structure on Nanoparticle Surfaces

Arizona State University, Scottsdale AZ

Investigators

Abstract

With this award, the Chemical Measurement and Imaging Program of the Division of Chemistry is funding Professors Peter Crozier and Peter Rez at Arizona State University to develop a tool for probing the nanoscale chemistry of materials surfaces. This will provide an approach for understanding the way in which nanoparticles interact and influence their environment. The knowledge that is expected to emerge from this work could have wide applications in many fields where nanoparticle surfaces are important including catalysis, sensors and the life sciences. Graduate students and undergraduate researchers are expected to gain valuable training at the interface of nanomaterials and chemistry. Educational outreach programs associated with this project are targeting K-12 children with emphasis on Hispanic and Native American student sub-populations. The project exploits new developments in the field of transmission electron microscopy and electron energy-loss spectroscopy which permit vibrational spectroscopy to be performed with a focused electron beam of 0.1 nanometer in diameter. A major goal is to develop methodologies for probing vibrational surface states with high spatial resolution without significantly damaging the surface or removing surface adsorbates. A combination of experimental and modelling work is employed to optimize spectral acquisition and analysis techniques. The ultimate spatial resolution is influenced by the length scale of the electrostatic interaction between the electron beam and the sample. The spatial resolution and sensitivity of the approach for detecting a number of common chemical functional groups on a variety of metal and oxide nanoparticles surfaces will be determined. This project will provide the scientific community with a new method for probing fundamental chemical processes with nanometer resolution.