Research Pioneered and Reported First by Professor Somorjai
and Co-workers


Clean Surface Reconstruction

· First report of clean transition metal surface reconstruction.

Surface Structures on the Clean Platinum (100) Surface, S. Hagstrom, H.B. Lyon, and G.A. Somorjai, Phys. Rev. Lett. 15(11), 491–493 (1965).
· First surface structure determination of an oxide film grown on a foreign substrate—Fe3O4 on Pt(111).
Surface Structure Determination of an Oxide Film Grown on a Foreign Substrate: Fe3O4 Multilayer on Pt(111) Identified by Low Energy Electron Diffraction, W. Weiss, A. Barbieri, M.A. Van Hove, and G.A. Somorjai, Phys. Rev. Lett. 71(12), 1848–1851 (1993).
· First report of large vibrational amplitude of water molecules on ice crystal surfaces leading to disorder and surface “softness.”
Molecular Surface Structure of Ice(0001): Dynamical Low-Energy Electron Diffraction,  Total-Energy Calculations and Molecular Dynamics Simulations, N. Materer, U. Starke, A. Barbieri, M.A. Van Hove and G.A. Somorjai, Surface Science, 381, 190 (1997).

Molecular Surface Structure of a Low-Temperature Ice Ih(0001) Crystal, N. Materer, U. Starke, A. Barbieri, M.A. Van Hove, G.A. Somorjai, G.-J. Kroes, and C. Minot, Journal of Physical Chemistry, 99, 6267–6269 (1995).

· Determination of surface reconstruction of sodium chloride
Tensor Low-Energy Electron Diffraction Analysis of the Surface Structure of NaCl(100) Thin Films Grown on Pd(100) and Pt(111), J. G. Roberts, S. Hoffer, M. A. Van Hove, and G. A. Somorjai, Surf. Sci. 437, 75-85 (1999).
· Detection of ferroelectric ice film grown on Pt(111) single crysal.
Surface-Induced Ferroelectric Ice on Pt(111), X. Su, L. Lianos, Y. R. Shen, and G. A. Somorjai, Phys. Rev. Lett. 80, 1533-1536 (1998).


Surface Irregularities, Steps and Kinks.  Unique Chemisorption and Catalytic Activity

· First report of unique chemisorption and catalytic activity of surface irregularities, steps and kinks.

LEED Studies of Chemisorbed Gases on Stepped Surfaces of Platinum, B. Lang, R.W. Joyner and G.A. Somorjai, Surf. Sci. 30, 454–474 (1972).

The Reactivity of Low Index [(111) and (100)] and Stepped Platinum Single Crystal Surfaces, G.A. Somorjai, R.W. Joyner and B. Lang, Proc. R. Soc. Lond. A. 331, 335–346 (1972).

Molecular Beam Study of Hydrogen-Deuterium Exchange on Low- and High- Miller Index Platinum Single Crystal Surfaces, S.L. Bernasek, W.J. Siekhaus and G.A. Somorjai, Phys. Rev. Lett. 30(24), 1202–1204 (1973).

Molecular Beam Study of the Mechanism of Catalyzed H2-D2 Exchange on Platinum Single Crystal Surfaces, S.L. Bernasek and G.A. Somorjai, J. Chem. Phys. 62(8), 3149–3161 (1975).

· Clean Step Reconstruction
Real-Space Multiple Scattering Theory Calculations of LEED Intensities for Stepped Surfaces, H.-G. Zhang, P.J. Rous, J.M. MacLaren, A. Gonis, M.A. Van Hove, and G.A. Somorjai, The Structure of Surfaces III,  Proc. ICSOS-3.  S.Y. Tong, M.A. Van Hove, K. Takayanagi and X.D. Xie, eds.  Springer-Verlag: Berlin, Heidelberg, New York, 1991. p. 144.


First study of the surface Debye temperature (mean displacement of surface atoms) of metals measured by low-energy electron diffraction
 

Surface Debye Temperature of the (100), (111), and (110) Faces of Platinum (H.B. Lyon and G.A. Somorjai), J. Chem. Phys. 44(10), 3707–3711 (1966).


First study of surface melting and freezing of liquid metal surfaces by low-energy electron diffraction

LEED Studies of Surface Melting and Freezing of Lead, Bismuth, and Tin Single Crystal Surfaces, R.M. Goodman and G.A. Somorjai, J. Chem. Phys. 52(12), 6325–6331 (1970).

LEED Studies of Liquid Lead, Bismuth, and Tin Surfaces, R.M. Goodman and G.A. Somorjai, J. Chem. Phys. 52(12), 6331–6335 (1970).


First report of studies of the surface structures of molecular crystals by low-energy electron diffraction

LEED Studies of Molecular Crystals: The Surface Structures of Vapor Grown Ice and Naphthalene, L.E. Firment and G.A. Somorjai, J. Chem. Phys. 63(2), 1037–1038 (1975).


Organic Monolayers on Metals

· First study of organic monolayers on metals by low-energy electron diffraction.

Low Energy Electron Diffraction Studies of the Adsorption of Unsaturated Hydrocarbons and Carbon Monoxide on the Platinum (111) and (100) Single Crystal Surfaces, A.E. Morgan and G.A. Somorjai, J. Chem. Phys. 51(8), 3309–3320 (1969).
· Rules proposed to predict the structure of adsorbed atomic and molecular monolayers on crystal surfaces.
Simple Rules to Predict the Structure of Adsorbed Gases on Crystal Surfaces, F.J. Szalkowski and G.A. Somorjai, J. Chem. Phys. 54(1), 389–399 (1971).
 

Surface Structure Analysis of Organic Monolayers

· First report of surface structure analysis of an organic molecule by LEED surface crystallography: ethylene on Pt(111).

Dynamical LEED Study of C2H2 and C2H4 Chemisorption of Pt(111): Evidence for the Ethylidyne (-C-CH3) Group, L.L. Kesmodel, L.H. Dubois, and G.A. Somorjai, Chem. Phys. Lett. 56(2), 267–271 (1978).
· First report of adsorbate-induced restructuring of metals by an organic molecule.
Molecule-Induced Displacive Reconstruction in a Substrate Surface: Ethylidyne Adsorbed on Rh(111) Studied by Low-Energy-Electron Diffraction, A. Wander, M.A. Van Hove, and G.A. Somorjai, Phys. Rev. Lett. 67(5), 626–628 (1991).
First Study of Coadsorption—Its Chemical and Structural Effects.
The Strong Influence of Potassium on the Adsorption of CO on Platinum Surfaces. A Thermal Desorption Spectroscopy and High-Resolution Electron Energy Loss Spectroscopy Study, E.L. Garfunkel, J.E. Crowell, and G.A. Somorjai, J. Phys. Chem. 86, 310–313 (1982).

The Coadsorption of Potassium and CO on the Pt(111) Crystal Surface: A TDS, HREELS and UPS Study, J.E. Crowell, E.L. Garfunkel and G.A. Somorjai, Surf. Sci. 121, 303–320 (1982).


Catalytic Reaction Studies on Single Crystal Surfaces

· First report of catalytic reaction studies on single crystal surfaces at atmospheric pressure.

The Hydrogenolysis of Cyclopropane on a Platinum Stepped Single Crystal at Atmospheric Pressure, D.R. Kahn, E.E. Petersen, and G.A. Somorjai J. Catal. 34, 294–306 (1974).
· Mechanism for catalytic hydrocarbon conversion over platinum.
The Reactivity and Composition of Strongly Adsorbed Carbonaceous Deposits on Platinum. Model of the Working Hydrocarbon Conversion Catalyst, S.M. Davis, F. Zaera, and G.A. Somorjai, J. Catal. 77, 439–459 (1982).

Surface Structure and Temperature Dependence of Light-Alkane Skeletal Rearrangement Reactions Catalyzed over Platinum Single-Crystal Surfaces, S.M. Davis, F. Zaera, and G.A. Somorjai, J. Am. Chem. Soc. 104, 7453–7461 (1982).

Hydrogenation of Ethylene Over Platinum (111) Single-Crystal Surfaces, F. Zaera and G.A. Somorjai, J. Am. Chem. Soc. 106(8), 2288–2293 (1984).

· First study of ammonia synthesis on iron single-crystal surfaces.
Structure Sensitivity in the Iron Single-Crystal Catalyzed Synthesis of Ammonia, N.O. Spencer, R.C. Schoonmaker and G.A. Somorjai, Nature 294(5842), 643–644 (1981).
· First study of reaction oscillation at high pressures on single crystals.
The Oscillatory Behavior of the CO Oxidation Reaction at Atmospheric Pressure Over Platinum Single Crystals: Surface Analysis and Pressure Dependent Mechanisms, R.C. Yeates, J.E. Turner, A.J. Gellman and G.A. Somorjai, Surf. Sci. 149(l), l75–190 (l985).
· Detection of Reaction Intermediates During High Pressure Catalytic CO Oxidation on Pt(111).
High Pressure CO Oxidation on Pt(111) Monitored with Infrared-visible Sum Frequency Generation (SFG), X. Su, P.S. Cremer, Y.R. Shen and G.A. Somorjai, Journal of  American Chemical Society, 119, 3994 (1997).
· First study of hydrodesulfurization over single crystals.
A Radiotracer (14C) and Catalytic Study of Thiophene Hydrodesulfurization on the Clean and Carbided Mo(100) Single-Crystal Surface, M.E. Bussell and G.A. Somorjai, J. Catal. 106, 93–104 (1987).

Catalytic Hydrodesulfurization Over The Mo(100) Single Crystal  Surface  I. Kinetics and Overall Mechanism, A.J. Gellman, D. Neiman, and G.A. Somorjai, J. Catal. 107, 92–102 (1987).

· The mechanism of ethylene and light olefin hydrogenation over platinum. First report that weakly bonded adsorbates (?-bonded olefins) are the reaction intermediates that turn over. Strongly chemisorbed adsorbates are spectators during the reaction.
Monitoring Surfaces on the Molecular Level during Catalytic Reactions at High Pressure by Sum Frequency Generation Vibrational Spectroscopy and Scanning Tunneling Microscopy, P.S. Cremer, B.J. McIntyre, M. Salmeron, Y.-R. Shen, and G.A. Somorjai, Catal. Lett. 34(1/2), 11-18 (1995).

Ethylene Hydrogenation on Pt(111) Monitored in Situ at High Pressures Using Sum Frequency Generation, P.S. Cremer, X. Su, Y.R. Shen and G.A. Somorjai, J. Am. Chem. Soc. 118(12), 2942–2949 (1996).

The Hydrogenation and Dehydrogenation of Propylene on Pt(111) Studied by Sum Frequency Generation from UHV to Atmospheric Pressure, P.S. Cremer, X. Su, Y.R. Shen, and G.A. Somorjai, J. Phys. Chem. 100(40), 16302-16309 (1996).

1,3- and 1,4-cyclohexadiene Reaction Intermediates in Cyclohexane Hydrogenation and Dehydrogenation on Pt(111) Crystal Surface: A Combined Reaction Kinetics and Surface Vibrational Spectroscopy Study Using Sum Frequency, X. Su, R. Shen, and G.A. Somorjai, J. Mol. Catal. A 141, 9 (1999).

· First measurement of an absolute turnover rate in heterogeneous catalysis.
The First Measurement of an Absolute Surface Concentration of Reaction Intermediates in Ethylene Hydrogenation, P.S. Cremer, X. Su, Y.R. Shen, and G.A. Somorjai, Catal. Lett. 40(3,4),143–145 (1996).
· First report of hydrogen production from the photocatalyzed dissociation of water vapor.
Hydrogen Production from Photolysis of Steam Adsorbed onto Platinized SrTiO3, R.G. Carr and G. A. Somorjai, Nature 290, 576–577 (1981).
· Lewis acidity as an explanation for oxide promotion of metals in catalytic reactions.
Lewis Acidity as an Explanation for Oxide Promotion of Metals: Implications of its Importance and Limits for Catalytic Reactions, A.B. Boffa, C. Lin, A.T. Bell and G.A. Somorjai, Catal. Lett. 27(3/4), 243–249 (1994).
· First report of nanocatalysis by the tip of a scanning tunneling microscope operating inside a reactor cell.
Nanocatalysis by the Tip of a Scanning Tunneling Microscope Operating Inside a Reactor Cell, B.J. McIntyre, M. Salmeron, and G.A. Somorjai, Science 265, 1415–1418 (1994).
· First report of using sum frequency generation (SFG) vibrational spectroscopy to monitor catalytic reaction intermediates at high pressures on single crystal model catalysts
Ethylene Hydrogenation on Pt(111) Monitored In Situ at High Pressures Using Sum Frequency Generation, P.S. Cremer, X. Su, Y.R . Shen, and G.A. Somorjai, J. Am. Chem. Soc. 118, 2942-2949 (1996).

The Hydrogenation and Dehydrogenation of Isobutene on Pt(111) Monitored by IR-Visible Sum Frequency Generation and Gas Chromatography, P.S. Cremer, X. Su, Y.R. Shen, and G.A. Somorjai, J. Chem. Soc., Faraday Trans. 92, 4717-4722 (1996).

· Formation of hydrocarbons by short contact time nozzle beam reactions.
Formation of CmHn (M >= 3, N <= M) Hydrocarbons from C-1 and C-2 Molecules by High-Temperature (>= 1000 Degrees C), Short-Contact-Time (1-10 Ms) Nozzle Beam Reactions, L. Romm and G. A. Somorjai, Cat. Lett. 64, 85-93 (2000).
· SFG study of CO dissociation at high  pressures on platinum single crystal surfaces
Sum Frequency Generation Spectroscopic Study of CO Adsorption and Dissociation on Pt(111) at High Pressure and Temperature, K. Y. Kung, P. Chen, F. Wei, Y. R. Shen, and G. A. Somorjai, Surf. Sci, 463, 627 (2000).

Surface Structure Sensitivity of High-Pressure CO Dissociation on Pt(557), Pt(100) and Pt(111) Using Sum Frequency Generation Surface Vibrational Spectroscopy, K. McCrea, J. S. Parker, P. Chen, G. A. Somorjai, Surf. Sci. 494, 238 (2001).


Adsorbate Induced Restructuring

· First report of the dominant role of adsorbate-induced restructuring of surfaces.

Adsorbate-Induced Restructuring of Surfaces, G.A. Somorjai and M.A. Van Hove, Prog. Surf. Sci. 30(3/4), 201–231 (1989).
· First report of surface restructuring-induced bond breaking and catalysis.
Surface Restructuring as a Mechanism for Bond Breaking and Catalytic Reactions at Metal Surfaces, G.A. Somorjai and M.A. Van Hove, Catal. Lett. 1(12) 433–438 (1988).
· First scanning tunneling microscope study of coadsorption-induced surface reconstruction.
Coadsorbate Induced Reconstruction of a Stepped Pt(111) Surface by Sulfur and CO: A Novel Surface Restructuring Mechanism Observed by Scanning Tunneling Microscopy, J.D. Batteas, J.C. Dunphy, G.A. Somorjai, and M. Salmeron, Phys. Rev. Lett. 77(3), 534–537 (1996).


Effects of Pressure and External Potential on CO Bonding

· First report of high-pressure-induced changes in CO bonding on Pt(111).

The Pressure Dependence (10-10–700 Torr) of the Vibrational Spectra of Adsorbed CO on Pt(111) Studied by Sum Frequency Generation, X. Su, P.S. Cremer, Y.R. Shen, and G.A. Somorjai, Phys. Rev. Lett. 77(18), 3858–3860 (1996).

Sum Frequency Generation Spectroscopic Study of CO Adsorption and Dissociation on Pt(111) at High Pressure and Temperature, K. Y. Kung, P. Chen, F. Wei, Y. R. Shen, and G. A. Somorjai, Surf. Sci, 463, 627 (2000).

Dense Structures Formed by CO on Rh(111) Studied by Scanning Tunneling Microscopy, P. Cernota, K. Rider, H. A. Yoon, M. Salmeron, and G.A. Somorjai, Surf. Sci. 445, 249-255 (2000).

· Change of orientation of adsorbed molecules with variation of external potential at the solid-liquid interface detected by vibrational spectroscopy.
Sum Frequency Generation of CO on (111) and Polycrystalline Platinum Electrode Surfaces:  Evidence for SFG Invisible Surface CO, S. Baldelli, N. Markovic, P. Ross, Y. R. Shen, and G.A. Somorjai, J. Phys. Chem. B 103, 8920-8925 (1999).

Potential Dependent Orientation of Acetonitrile on Platinum (111) Electrode Surface Studied by Sum Frequency Generation, S. Baldelli, G. Mailhot, P. Ross, Y. R. Shen, and G. A. Somorjai, J. Phys. Chem. 105, 654-662 (2001).

Metal Nano-Cluster Arrays

· First report of fabrication of ordered arrays of nano-clusters as model catalysts by electron beam lithography.

The Fabrication of "High Technology" Catalysts, F.H. Ribeiro and G.A. Somorjai, Recl. Trav. Chim. Pays-Bas 113, 419–422 (1994).

Model Catalysts Fabricated by Electron Beam Lithography:  AFM and TPD Surface Studies and Hydrogenation/Dehydrogenation of Cyclohexene + H2 on a Pt Nanoparticle Array Supported by Silica, A.S. Eppler, J. Zhu, E.A. Anderson, and G.A. Somorjai, Top. in Cat. 13, 33-41 (2000).

Thermal and Chemical Stability and Adhesion Strength of Pt Nanoparticle Arrays Supported on Silica Studied by TEM and AFM, A.S. Eppler, G. Rupprechter, E.A. Anderson, and G.A. Somorjai, J. Phys. Chem. B 104, 7286-7292 (2000).

Surface Enhanced Sum Frequency Generation of Carbon Monoxide Adsorbed on Platinum Nanoparticle Arrays, S. Baldelli, A.S. Eppler, E. Anderson, Y.R. Shen, and G.A. Somorjai, J.. Chem. Phys. 113, 5432 (2000).

· Two-step synthesis of metal nanoparticles encapsulated in mesoporous silica
Novel Two-Step Synthesis of Controlled Size and Shape Platinum Nanoparticles Encapsulated in Mesoporous Silica, Z. Konya, V. F. Puntes, I. Kiricsi, J. Zhu, P. Alivisatos, G. A. Somorjai, Catal Lett. 81, 137 (2002).

Nanocrystal Templating of Silica Mesopores with Tunable Pore Sizes, Zoltan Konya, Victor F. Puntes, Imre Kiricsi, A. Paul Alivisatos and Gabor A. Somorjai, Nano Lett., 2, 907 (2002).

Polymer Surfaces

· First study of the surface structures of polymers by IR+visible sum frequency vibrational spectroscopy.

 Studies of Surface Structures and Compositions of Polyethylene and Polypropylene by IR+Visible Sum Frequency Vibrational Spectroscopy, D. Zhang, Y.R. Shen, and G.A. Somorjai, Chem. Phys. Lett. 281, 394 (1997).
· First study of surface structure–mechanical property relationship for polymer surfaces.
Surface Structure-Mechanical Property Relationship of Low Density Polyethylene (LDPE): An IR+Visible Sum Frequency Generation (SFG) Spectroscopy and Atomic Force Microscopy (AFM) Study, D.H. Gracias, D. Zhang, Y.R. Shen, and G.A. Somorjai, Trib. Lett. 4, 231 (1997).
· First report of changes of polymer surface composition with changing interface from solid-gas to solid-liquid.
An In-Situ IR+Visible Sum Frequency Spectroscopic Study : Surface Structural Changes of A Polymer in Response to An Aqueous Environment, D. Zhang, R. S. Ward, Y. R. Shen and G. A. Somorjai, Journal of Physical Chemistry, 38(2), (05/97)674 - 675.
· First study of structural changes during glass transition at polymer surfaces by vibrational spectroscopy.
A Study of the Glass Transition of Polypropylene Surfaces by Sum-Frequency Vibrational Spectroscopy and Scanning Force Microscopy, D.H. Gracias, D. Zhang, L. Lianos, W. Ibach, Y.R. Shen, and G.A. Somorjai, J. Chem. Phys. 245, 277-284 (1999).
· Stretched polymer surfaces.  AFM and SFG Studies.
Stretched Polymer Surfaces: AFM Measured Microstructure and Mechanical Properties of Polyethylene Held in Tensile Deformation, A. Opdahl and G. A. Somorjai, J. Polym. Sci. Part B:Polymer Physics 39 (2001) 2236.

Correlation of Surface Molecular Composition to Nanoscale Elastic Behavior and Topography of stretched Polyurethane Films, E. Amitay-Sadovsky, K. Komvopoulos, Y. tian, G. A. Somorjai, Appl. Phys. Lett. 80, (2002) 1829.


Surface Science of Polymerization Catalysis

· First study of the surface science of polymerization catalysis.  Formation of polyethylene and polypropylene on thin films of MgCl2/TiCl4/AlR3,

Ethylene and Propylene Polymerization Catalyzed by a Model Ziegler-Natta Catalyst prepared by Gas Phase Deposit of Magnesium Chloride and Titanium Chloride Thin Films,  E. Magni and G.A. Somorjai, Catalytic Letters, 35, 205-214 (1995).

Surface Science Study of Model Ziegler-Natta Catalysts, E. Magni and G.A. Somorjai, Surface Science, 377, 824, (1997).

Direct Measurement of Polymer Growth Rate in a Model Ziegler-Natta Polymerization System Using Laser Reflection Interferometry, S.H. Kim, G. Vurens, and G.A. Somorjai, J. Catal. 193, 171-175 (2000).

Surface Characterization of the TiClx/MgCl2 Model Ziegler-Natta Polymerization Catalysts:  Adsorption Site Studies Using Mesitylene Thermal Desorption, S.H. Kim, C.R. Tewell, G.A. Somorjai, Langmuir. 16, 9414 (2000)


Instrumentation

· Construction of the first low pressure-high pressure cell that combines high vacuum technology required for surface analysis with the high pressure cell necessary for studies of catalytic reactions on all area crystal surfaces

New Instrumentation and Techniques to Monitor Chemical Surface Reactions on Single Crystals over a Wide Pressure Range (10-8-105 Torr) in the Same Apparatus, D.W. Blakely, E.I. Kozak, B.A. Sexton, and G.A. Somorjai, J. Vac. Sci. Technol. 13(5), 1091 (1976).
 
with liquid phase reaction cell
 
An Ultrahigh Vacuum Chamber Equipped with a Liquid Phase Reaction Cell, D.E. Gardin and G.A. Somorjai, Rev. Sci. Instrum. 64(5), 1304 (1993).
 
with high pressure-high temperature scanning tunneling microscope
High Pressure, High Temperature Scanning Tunneling Microscopy, J.A. Jensen, K.B. Rider, Y. Chen, M. Salmeron, and G.A. Somorjai, J. Vac. Sci. 17, 1080-1084 (1999).
 
with sum frequency generation (SFG) – vibrational spectroscopy
Monitoring Surfaces on the Molecular Level during Catalytic Reactions at High Pressure by Sum Frequency Generation Vibrational Spectroscopy and Scanning Tunneling Microscopy, P.S. Cremer, B.J. McIntyre, M. Salmeron, Y.R. Shen, and G.A. Somorjai, Catal. Lett. 34(1/2), 11-18 (1995).
· Molecular beam surface scattering apparatus for reaction studies using clean single crystal surfaces
Molecular Beam Scattering from Single Crystal Surfaces under Ultrahigh Vacuum Conditions, L.A. West, E.I. Kozak, and G.A. Somorjai, J. Vac. Sci. Technol. 8(2), 430-436 (1971).
with velocity and angular distribution measurements
Design of a Molecular Beam Surface Scattering Apparatus for Velocity and Angular Distribution Measurements, S.T. Ceyer, W.J. Siekhaus, and G.A. Somorjai, J. Vac. Sci. Technol. 19(3), 726 (1981).
with internal energy distribution measurements
Energy Redistribution among Internal States of Nitric Oxide Molecules upon Scattering from Pt(111) Crystal Surface, M. Asscher, W.L. Guthrie, T.-H. Lin, and G.A. Somorjai, J. Chem. Phys. 78(11), 6992 (1983).