People | Faculty | John T. Yates Jr.
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John T. Yates Jr. Department of Chemistry |
Professor Yates' research group is engaged in a variety of surface chemistry studies on both single crystal and high area substrates. A number of new surface measurement techniques are being developed and used in the group for the study of molecular processes on metal, semi-conductor, and insulator surfaces. The group is engaged in the study of the molecular structure and chemical reactivity of surface species. Among the experimental techniques employed on single crystal surfaces are LEED (1), ESDIAD (2), EELS (3), and IRAS (4). Kinetic and mechanistic studies on single crystal surfaces are also being carried out using molecular beam methods, photochemical methods (5), TPD procedures (6) and STM imaging (7). In addition, parallel studies of surface chemistry on supported metal cluster surfaces on metal oxide surfaces and on carbon nanotube surfaces are being undertaken using high sensitivity transmission IR methods.
A new activity currently being developed is an STM probe to work at 5K. This will be used to study the fundamentals of the electrical conductivity of single adsorbed molecules.
One of the most powerful structural methods employed (ESDIAD) depends on the fact that a molecule chemisorbed on a single crystal surface may be dissociated by electron bombardment, yielding positive ions. Using this apparatus, we may image the ion emission directions. Since the ions escape along directions closely similar to the surface species' bond direction, we obtain information on bond orientation, surface symmetry, and the character of high amplitude vibrational modes. Two separate digitized ESDIAD systems are available for studies of bonding on metals and on semiconductor crystals. The incorporation of time-of-flight capability with ESDIAD permits individual C-H bond directions to be probed in adsorbed species.
1. LEED = Low Energy Electron Diffraction. A widely used method for determining the two-dimensional lattice character of an ordered layer adsorbed on a single crystal surface.
2. ESDIAD = Electron Stimulated Desorption-Ion Angular Distribution. A method useful for studying bond directionality in adsorbed species by imaging positive ion fragment emission directions. Time-of-flight capabilities permit separate imaging of C-H and C-O bond directions.
3. EELS = Electron Energy Loss Spectroscopy. A method for studying the vibrational frequencies of adsorbed molecules using a monoenergetic electron beam and measuring discrete losses in electron energy which correspond to surface vibrational excitations.
4. IRAS = Infrared Reflection-Absorption Spectroscopy. A method for studying vibrations of adsorbed species which possesses superior energy resolution. The method also works well for the study of surfaces in dense gas media.
5. Photochemical surface kinetics involving electronic excitation of surface processes such as dissociation and desorption.
6. TPD = Temperature Programmed Desorption. A method for controlled desorption from a surface using a known temperature function coupled with mass spectrometric detection of desorbing species.
7. STM= Scanning Tunneling Microscopy.
"Adsorption of CF4 on Internal and External Walls of Opened Single Walled Carbon Nanotubes - A Vibrational Spectroscopy Study," O. Byl, P. Kondratyuk, S. Forth, S. FitzGerald, J. T. Yates, Jr., L. Chen and J. K. Johnson, J. Am. Chem. Soc., 2003, 125, 5889
"The Effect of Atomic Steps on Adsorption and Desorption of CO on Ru(109)," T. Zubkov, G. A. Morgan, Jr., J. T. Yates, Jr., O. Kuhlert, M. Lisowski, R. Schillinger, D. Fick and H. J. Jansch, Surface Science, 2003, 526, 57
"STM Studies of Defect Production on the TiO2(110)-(1x1) and TiO2(110)-(1x2) Surfaces Induced by UV Irradiation," S. Mezhenny, P. Maksymovych, T. L. Thompson, O. Diwald, D. Stahl, S. D. Walck and J. T. Yates, Jr., Chem. Phys. Lett., 2003, 369, 152
"Electrostatic Field Enhancement of Al(111) Oxidation," I. Popova, V. Zhukov and J. T. Yates, Jr., Phys. Rev. Lett., 2002, 89, 276101
"Surface Aligned Ion-Molecule Reaction: Direct Observation of Initial and Final Ion Momenta," J-G. Lee, S-H. Hong, J. Ahner and J. T. Yates, Jr., Phys. Rev. Lett., 2002, 89, 253202-1
"Dissociation of CH3I on the Al(111) Surface - An STM and Density Functional Theory Study," S. Mezhenny, D. C. Sorescu, P. Maksymovych and J. T. Yates, Jr., J. Am. Chem. Soc., 2002, 124, 14202
"Spectroscopic Detection of CO Dissociation on Defect Sites on Ru(109): Implications for Fischer-Tropsch Catalytic Chemistry," T. Zubkov, G. Morgan, Jr. and J. T. Yates, Jr., Chem. Phys. Lett., 2002, 362, 181
"Adsorption Geometry of 4-Picoline Chemisorbed on the Cu(110) Surface: A Study of Forces Controlling Molecular Self-Assembly," J.-G. Lee, J. Ahner and J. T. Yates, Jr., J. Am. Chem. Soc., 2002, 124, 2772
"Oxygen-containing Functional Groups on Single-Wall Carbon Nanotubes-NEXAFS and Vibrational Spectroscopic Studies," A. Kuznetsova, I. Popova, J. T. Yates, Jr., M. J. Bronikowski, C. B. Huffman, J. Liu, R. E. Smalley, H. H. Hwu and J. G. Chen, J. Am. Chem. Soc., 2001, 123, 10699
"Molecular Triangulation-Finding the Conformation of Adsorbed Self-Assembled Organic Molecules," J.-G. Lee, J. Ahner, P. Maksymovych and J. T. Yates, Jr., Chem. Phys. Lett., 2001, 340, 21
Awards
Sherman Fairchild Distinguished Scholar, Caltech, 1977-78; Department of Commerce Gold Medal, 1981; Kendall Award (ACS) in Surface Chemistry, 1986; President's Distinguished Research Award, University of Pittsburgh, 1989; M. W. Welch Award (AVS), 1994; A. von Humboldt Research Prize, 1995; National Academy of Sciences, 1996; Pittsburgh Award (ACS), 1998; Adamson Award (ACS) in Surface Chemistry, 1999; J.W. Linnett Visiting Professor Lectureship, Cambridge University, England, 2000; Japanese Society for the Promotion of Science Fellowship (JSPS), 2002
Selected Publications
"Adsorption of CF4 on Internal and External Walls of Opened Single Walled Carbon Nanotubes - A Vibrational Spectroscopy Study," O. Byl, P. Kondratyuk, S. Forth, S. FitzGerald, J. T. Yates, Jr., L. Chen and J. K. Johnson, J. Am. Chem. Soc., 2003, 125, 5889
"The Effect of Atomic Steps on Adsorption and Desorption of CO on Ru(109)," T. Zubkov, G. A. Morgan, Jr., J. T. Yates, Jr., O. Kuhlert, M. Lisowski, R. Schillinger, D. Fick and H. J. Jansch, Surface Science, 2003, 526, 57
"STM Studies of Defect Production on the TiO2(110)-(1x1) and TiO2(110)-(1x2) Surfaces Induced by UV Irradiation," S. Mezhenny, P. Maksymovych, T. L. Thompson, O. Diwald, D. Stahl, S. D. Walck and J. T. Yates, Jr., Chem. Phys. Lett., 2003, 369, 152
"Electrostatic Field Enhancement of Al(111) Oxidation," I. Popova, V. Zhukov and J. T. Yates, Jr., Phys. Rev. Lett., 2002, 89, 276101
"Surface Aligned Ion-Molecule Reaction: Direct Observation of Initial and Final Ion Momenta," J-G. Lee, S-H. Hong, J. Ahner and J. T. Yates, Jr., Phys. Rev. Lett., 2002, 89, 253202-1
"Dissociation of CH3I on the Al(111) Surface - An STM and Density Functional Theory Study," S. Mezhenny, D. C. Sorescu, P. Maksymovych and J. T. Yates, Jr., J. Am. Chem. Soc., 2002, 124, 14202
"Spectroscopic Detection of CO Dissociation on Defect Sites on Ru(109): Implications for Fischer-Tropsch Catalytic Chemistry," T. Zubkov, G. Morgan, Jr. and J. T. Yates, Jr., Chem. Phys. Lett., 2002, 362, 181
"Adsorption Geometry of 4-Picoline Chemisorbed on the Cu(110) Surface: A Study of Forces Controlling Molecular Self-Assembly," J.-G. Lee, J. Ahner and J. T. Yates, Jr., J. Am. Chem. Soc., 2002, 124, 2772
"Oxygen-containing Functional Groups on Single-Wall Carbon Nanotubes-NEXAFS and Vibrational Spectroscopic Studies," A. Kuznetsova, I. Popova, J. T. Yates, Jr., M. J. Bronikowski, C. B. Huffman, J. Liu, R. E. Smalley, H. H. Hwu and J. G. Chen, J. Am. Chem. Soc., 2001, 123, 10699
"Molecular Triangulation-Finding the Conformation of Adsorbed Self-Assembled Organic Molecules," J.-G. Lee, J. Ahner, P. Maksymovych and J. T. Yates, Jr., Chem. Phys. Lett., 2001, 340, 21