Novel Analytical Techniques Based on an Enhanced Electron Attachment Process

Sensitive and selective detection of dense non-aqueous liquids (DNAPL), volatile organic compounds (VOC), and other organics, such as polychlorinated biphenyls (PCB), is an area of importance to the DOE's environmental restoration program. Current negative-ion based analytical methods for the detection of these compounds rely on their propensity to form negative ions (in their ground electronic states). However, for compounds with smaller electron capture cross sections, including PCBs with few chlorine atoms and non-chlorinated VOCs, these methods are considerably less sensitive. The objective of our research program is to develop novel analytical techniques that can be expected to be applicable for a wide variety of molecules with high sensitivity. These are based on the recently discovered enhanced negative ion formation process involving electron attachment to highly-Rydberg states of molecules. We are using two approaches to produce the precursor highly-excited states; one is laser excitation, and the other is discharge based