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

化学系的化学测量和成像项目将资助亚利桑那州立大学的Peter Crozier和Peter Rez教授开发一种用于探测材料表面纳米级化学的工具。这将为理解纳米颗粒相互作用和影响其环境的方式提供一种方法。期望从这项工作中产生的知识可以广泛应用于纳米颗粒表面很重要的许多领域，包括催化，传感器和生命科学。研究生和本科生的研究人员有望在纳米材料和化学的界面上获得宝贵的训练。与该项目相关的教育推广项目针对的是K-12儿童，重点是西班牙裔和美洲原住民学生群体。该项目利用了透射电子显微镜和电子能量损失光谱领域的新发展，允许用直径为0.1纳米的聚焦电子束进行振动光谱。一个主要目标是开发具有高空间分辨率的探测振动表面状态的方法，而不会严重破坏表面或去除表面吸附物。采用实验和建模相结合的方法来优化光谱采集和分析技术。最终空间分辨率受电子束与样品之间静电相互作用的长度尺度的影响。该方法用于检测各种金属和氧化物纳米颗粒表面上的一些常见化学官能团的空间分辨率和灵敏度将被确定。该项目将为科学界提供一种以纳米分辨率探测基本化学过程的新方法。

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.