This research project, supported in the Analytical and Surface Chemistry Program, focusses on the interaction of low energy polyatomic ions with adsorbate covered metal surfaces. During the tenure of this thirty-three month grant, Professor Luke Hanley and his students at the University of Illinois at Chicago will seek to develop an understanding of the surface induced dissociation of polyatomic ions for application in analytical mass spectrometry, and to investigate the deposition of energy into multilayers of adsorbates. A tandem quradrupole mass spectrometer with an ultra-high vacuum scattering chamber, developed recently by Professor Hanley under NSF grant CHE- 9220393, will be used in these studies. This research combines experimental and computational methods to study the interaction of low energy polyatomic ions with adsorbate covered metal surfaces. A detailed understanding of polyatomic ion-surface collisions is important to the development of surface induced dissociation (SID) as a sample introduction technique in bioanalytical mass spectrometry. Such an understanding is also important to the development of surface modification methodologies that are widely used in materials processing.