@article{trasca_cole_coffey_krim_2008, title={Gas adsorption on a C-60 monolayer}, volume={77}, ISSN={["1550-2376"]}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-42449113449&partnerID=MN8TOARS}, DOI={10.1103/physreve.77.041603}, abstractNote={The adsorption geometry of various gases on top of a C60 monolayer is investigated. The potential energy experienced by an adsorbate atom in the vicinity of a C60 molecule consists of Lennard-Jones interactions integrated over the spherical surface of the molecule. The adsorption potential exhibits strongly attractive sites which lead to a commensurate phase. The next adsorption sites are assumed on the basis of the symmetries of the triangular C60 array. The competition between different adsorption phases is solved by energy minimization. The onset pressure of each phase is computed and compared with experimental data for Kr on top of a C60 monolayer.}, number={4}, journal={PHYSICAL REVIEW E}, author={Trasca, R. A. and Cole, M. W. and Coffey, T. and Krim, J.}, year={2008}, month={Apr} }
 @article{coffey_krim_2005, title={Impact of substrate corrugation on the sliding friction levels of adsorbed films}, volume={95}, ISSN={["0031-9007"]}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-27144466341&partnerID=MN8TOARS}, DOI={10.1103/physrevlett.95.076101}, abstractNote={We report a quartz crystal microbalance (QCM) study of sliding friction for solid xenon monolayers at 77 K on Cu(111), Ni(111), graphene/Ni(111), and C(60) substrates. Simulations have predicted a strong dependence of phononic friction coefficient (eta) on surface corrugation in systems with similar lattice spacing, eta approximately U(2)(0), but this has never before been shown experimentally. In order to make direct comparisons with theory, substrates with similar lattice spacing but varying amplitudes of surface corrugation were studied. QCM data reveal friction levels proportional to U(2)(0), validating current theoretical and numerical predictions. Measurements of Xe/C(60) are also included for comparison purposes.}, number={7}, journal={PHYSICAL REVIEW LETTERS}, author={Coffey, T and Krim, J}, year={2005}, month={Aug} }
 @article{coffey_urquhart_ade_2002, title={Characterization of the effects of soft X-ray irradiation on polymers}, volume={122}, ISSN={["1873-2526"]}, DOI={10.1016/S0368-2048(01)00342-5}, abstractNote={The physical and chemical effects of the soft X-ray irradiation of polymers have been systematically evaluated for photon energies just above the C 1s binding energy. This exposure causes radiation damage in the form of the loss of mass and changes to the chemical structure of the polymers. These effects are evident in the Near Edge X-ray Absorption Fine Structure (NEXAFS) spectra of the exposed polymers, posing a fundamental limit to the sensitivity of NEXAFS spectroscopy for chemical microanalysis. Quantitative understanding of the chemistry and kinetics of radiation damage in polymers is necessary for the successful and validated application of NEXAFS microscopy. This paper outlines a method for quantifying this radiation damage as a function of X-ray dose, and applies these methods to characterize the loss of mass and loss of carbonyl group functionality from a diverse series of polymers. A series of simple correlations are proposed to rationalize the observed radiation damage propensities on the basis of the polymer chemical structure. In addition, NEXAFS spectra of irradiated and virgin polymers are used to provide a first-order identification of the radiation chemistry.}, number={1}, journal={JOURNAL OF ELECTRON SPECTROSCOPY AND RELATED PHENOMENA}, author={Coffey, T and Urquhart, SG and Ade, H}, year={2002}, month={Jan}, pages={65–78} }