Robert G. Keesee

Robert G. Keesee

Researches chemistry of planetary atmospheres, gas-surface interactions and atmospheric aerosols

The World Within Reach
Robert G. Keesee
Associate Professor
 

College of Arts and Sciences
Department: Atmospheric and Environmental Sciences

Address:
ES 214
Phone:
518-442-4566

 

Introduction

The interest in natural and anthropogenic atmospheric aerosols is driven by their significant influence on the physical properties of the atmosphere including cloud formation and precipitation, electrical phenomena, radiative transfer, visibility and temperature. Chemical properties are also affected since aerosols present pathways for reactions, transport, and deposition that would not occur in the gas phase alone. The heterogeneous or multiphase chemistry in which atmospheric aerosol particles and droplets participate is considerably less well understood than the homogeneous gas phase chemistry of the atmosphere. As a recent example, this lack of understanding contributed to a failure of atmospheric chemical models to anticipate the springtime Antarctic stratospheric ozone depletion.

Our current research is directed at exploring the chemistry of aerosols. The goals are two-fold. One is to identify and quantify processes of chemical aging for atmospheric aerosol particles and the other is to determine the roles of these processes in altering the ability of particles to serve as nuclei for formation of cloud droplets.

Our research approach involves experimental investigation in the laboratory of fundamental processes. We are developing methods to study heterogeneous nucleation and condensation on aerosol particles, the processes of chemical aging of aerosol particles, and the effects of aging on the properties of aerosol particles. The experimental system being developed to scrutinize these processes involves the combination of electric levitation of single particles with thermal gradient diffusion and optical detection techniques. The electric levitation technique is a variation of the well-known Millikan oil drop experiment and allows the experimenter to interrogate a single micron-sized particle for extended periods that can be comparable to the residence time of a particle in the atmosphere. The thermal gradient diffusion technique creates a steady supersaturated environment for study of vapor-to-liquid nucleation. Laser spectroscopic methods that include Mie scattering and Raman scattering are being instituted for additional diagnostics.

Education

University of Colorado, Boulder, Colorado
Ph.D. in Physical Chemistry, 1979
 
University of Arizona, Tucson, Arizona
B.S. in Chemistry (honors) and Mathematics, 1975

Research Interests

Chemistry of planetary atmospheres, atmospheric aerosols, nucleation phenomena, ion solvation, gas-surface interactions, ion-molecule and ion-aerosol interactions, chemical and physical properties of molecular clusters and aerosols

Publications

R. G. Keesee, S. B. Hopf, and J. L. Moyers, "The Distribution and Characteristics of Particulate Sulfate in the Southwest Desert Atmosphere", Proc. Int'l Conf. on Environmental Sensing and Assessment (Las Vegas), Paper 23-6, September 1975 (published 1976).

A. W. Castleman, Jr., P. M. Holland, and R. G. Keesee, "The Properties of Ion Clusters and Their Relationship to Heteromolecular Nucleation", J. Chem. Phys. 68, 1760-1767 (1978).

R. G. Keesee, N. Lee, and A. W. Castleman, Jr., "Atmospheric Negative Ion Hydration Derived from Laboratory Results and Comparison to Rocket-Borne Measurements in the Lower Ionosphere", J. Geophys. Res. 84, 3719-3722 (1979).

R. G. Keesee, N. Lee, and A. W. Castleman, Jr., "Properties of Clusters in the Gas Phase. 3. Hydration Complexes of CO3- and HCO3-", J. Am. Chem. Soc. 101, 2599-2604 (1979).

N. Lee, R. G. Keesee, and A. W. Castleman, Jr., "On the Correlation of Total and Partial Enthalpies of Ion Solvation and the Relationship to the Energy Barrier to Nucleation", J. Colloid Interface Sci. 75, 555-565 (1980).

R. G. Keesee and A. W. Castleman, Jr., "Heats of Formation of SO2Cl- and (SO2)2Cl-", J. Am. Chem. Soc. 102, 1446 (1980).

N. Lee, R. G. Keesee, and A. W. Castleman, Jr., "The Properties of Clusters in the Gas Phase IV. Complexes of H2O and HNOx clustering on NOx-", J. Chem. Phys. 72, 1089-1094 (1980).

R. G. Keesee, N. Lee, and A. W. Castleman, Jr., "Properties of Clusters in the Gas Phase. V. Complexes of Neutral Molecules onto Negative Ions", J. Chem. Phys. 73, 2195-2202 (1980).

R. G. Keesee and A. W. Castleman, Jr., "Gas-Phase Studies of Hydration Complexes of Cl- and I- and Comparison to Electrostatic Calculations in the Gas Phase", Chem. Phys. Lett. 74, 139-142 (1980).

K. I. Peterson, P. M. Holland, R. G. Keesee, N. Lee, T. D. Märk, and A. W. Castleman, Jr., "Studies of the Structure and Bonding of Inorganic Clusters", Surf. Sci. 106, 136-145 (1981).

A. W. Castleman, Jr. and R. G. Keesee, "Properties of Clusters in the Gas Phase" in Electron and Ion Swarms, L. G. Christophorou, Ed., Pergamon Press, New York, pp. 189-201 (1981).

A. W. Castleman, Jr., P. M. Holland, B. D. Kay, R. G. Keesee, T. D. Märk, K. I. Peterson, F. J. Schelling, and B. L. Upschulte, "Studies of Small Clusters: Relationship to Understanding Nucleation and Surfaces", J. Vac. Sci. Technol. 18, 586-588 (1981).

A. W. Castleman, Jr. and R. G. Keesee, "Nucleation and Growth of Stratospheric Aerosols", Ann. Rev. Earth Planet. Sci. 9, 227-249 (1981).

R. G. Keesee and A. W. Castleman, Jr., "The Chemical Kinetics of Aerosol Formation" in The Stratospheric Aerosol Layer, Topics in Current Physics 28, R. C. Whitten, Ed., Springer-Verlag, Berlin, pp. 69-92 (1982).

A. W. Castleman, Jr., P. M. Holland, and R. G. Keesee, "Ion Association Processes and Ion Clustering: Elucidating Transitions from the Gaseous to the Condensed Phase", Radiat. Phys. Chem. 20, 57-74 (1982).

R. P. Turco, O. B. Toon, R. C. Whitten, R. G. Keesee, and D. Hollenbach, "Noctilucent Clouds: Simulation Studies of Their Genesis, Properties, and Global Influence", Planet. Space Sci. 30, 1147-1181 (1982).

R. P. Turco, O. B. Toon, R. C. Whitten, R. G. Keesee, and D. Hollenbach, "A Study of Mesospheric Rocket Contrails Produced by Liquid-Fueled Rockets", Space Solar Power Rev. 3, 223-234 (1982).

W. J. Borucki, Z. Levin, R. C. Whitten, R. G. Keesee, L. A. Capone, O. B. Toon, and J. Dubach, "Predicted Electrical Conductivity Between 0 and 80 km in the Venusian Atmosphere", Icarus 51, 302-321 (1982).

A. W. Castleman, Jr., P. M. Holland, D. E. Hunton, R. G. Keesee, T. G. Lindeman, K. I. Peterson, F. J. Schelling, and B. L. Upschulte, "Studies of the Energetics and Structures of Clusters of Molecules about Ions Utilizing Laser Photodissociation and High Pressure Mass Spectrometric Techniques", Ber. Bunsenges. Phys. Chem. 86, 866-869 (1982).

R. P. Turco, O. B. Toon, R. C. Whitten, R. G. Keesee, and P. Hamill, "Importance of Heterogeneous Reactions to Tropospheric Chemistry: Studies with a One-Dimensional Model" in Heterogeneous Atmospheric Chemistry, Geophysics Monograph 26, D. R. Schryer, Ed., Am. Geophys. Union, Washington, DC, pp. 231-240 (1982).

R. P. Turco, O. B. Toon, R. C. Whitten, R. G. Keesee, and P. Hamill, "Simulation Studies of the Physical and Chemical Processes Occurring in the Stratospheric Clouds of the Mount St. Helens Eruptions of May and June, 1980", NASA Conf. Pub. 2240, A. Deepak, Ed., pp. 161-189 (1982).

A. W. Castleman, Jr., E. Hsieh, B. L. Upschulte, F.J. Schelling, R. G. Keesee, and P. M. Holland, "Some Considerations of the Dynamics of Ion-Molecule Cluster Reactions", Int. J. Mass Spectrom. Ion Phys. 47, 191-194 (1983).

R. P. Turco, O. B. Toon, R. C. Whitten, P. Hamill, and R. G. Keesee, "The 1980 Eruptions of Mount St. Helens: Physical and Chemical Processes in the Stratospheric Clouds", J. Geophys. Res. 88, 5299-5319 (1983).

A. W. Castleman, Jr. and R. G. Keesee, "Small Clusters: Aerosol Precursors", Aerosol Sci. Technol. 2, 145-152 (1983).

R. G. Keesee and A. W. Castleman, Jr., "Understanding the Middle Atmosphere via the Laboratory: Ion Cluster Investigations", Annales Geophysicae 1, 75-80 (1983).

R. P. Turco, O. B. Toon, R. C. Whitten, and R. G. Keesee, " Venus: Mesospheric Hazes of Ice, Dust, and Acid Aerosols", Icarus 53, 18-24 (1983).

K. I. Peterson, T. D. Märk, R. G. Keesee, and A. W. Castleman, Jr., "Thermochemical Properties of Gas-Phase Mixed Clusters: H2O/CO2 with Na+", J. Phys. Chem. 88, 2880-2883 (1984).

R. G. Keesee, R. Sievert-Hofmann, and A. W. Castleman, Jr., "Mass Spectral and Electric Deflection Study of Acetic Acid Clusters and Sulfur Trioxide/Water Clusters", Ber. Bunsenges. Phys. Chem. 88, 273-274 (1984).

R. G. Keesee and A. W. Castleman, Jr., "Some Considerations of Bonding" in Ionic Processes in the Gas Phase, M. A. Almoster Ferreira, Ed., NATO ASI Series C 118, 340-342 (1984).

A. W. Castleman, Jr. and R. G. Keesee, "Cluster Ion Association Reactions: Thermochemistry and Relationship to Kinetics" in Swarms of Ions and Electrons in Gases, W. Lindinger, T. D. Märk, and F. Howorka, Eds., Springer-Verlag, New York, pp. 167-193 (1984).

B. L. Upschulte, F. J. Schelling, R. G. Keesee, and A. W. Castleman, Jr., "Thermochemical Properties of Gas Phase Mixed Clusters: Water and Sulfur Dioxide with Na+ and Cl-", Chem. Phys. Lett. 111, 389-393 (1984).

J. J. Breen, K. Kilgore, K. Stephan, R. Hofmann-Sievert, B. D. Kay, R. G. Keesee, T. D. Märk, and A. W. Castleman, Jr., "The Use of Similarity Profiles in Studying Cluster Formation in Molecular Beams: Evidence for the Role of Preexisting Dimers", Chem. Phys. 91, 305-313 (1984).

R. G. Keesee and A. W. Castleman, Jr., "Ions and Cluster Ions: Experimental Studies and Atmospheric Observations", J. Geophys. Res. 90, 5885-5890 (1985).

A. W. Castleman, Jr., P. D. Dao, O. Echt, S. Morgan, J. J. Breen, K. Kilgore, and R. G. Keesee, "Studies of the Dynamics and Properties of Clusters", Surf. Sci. 156, 469-486 (1985).

B. L. Upschulte, R. J. Shul, R. Passarella, R. E. Leuchtner, R. G. Keesee, and A. W. Castleman, Jr., "Chemiluminescence of CS2+ Initiated by a Thermal Energy Charge Transfer Reaction with Ar+", J. Phys. Chem. 90, 100-104 (1986).

R. G. Keesee and A. W. Castleman, Jr., "Thermochemical Data on Gas-Phase Ion-Molecule Association and Clustering Reactons", J. Phys. Chem. Ref. Data 15, 1011-1071 (1986).

R. G. Keesee, R. Hofmann-Sievert, and A. W. Castleman, Jr., "The Interaction of Sulfur Trioxide with Water Clusters" in Chemistry of Multiphase Atmospheric Systems, W. Jaeschke, Ed., NATO ASI Series G 6, 501-505 (1986).

R. G. Keesee, A. W. Castleman, Jr., and T. D. Märk, "Electron-Cluster Interactions" in Swarm Studies and Inelastic Electron-Molecule Collisions, L. A. Pitchford, B. V. McKoy, A. Chutjian, and S. Trajmar, Eds., Springer-Verlag, New York, pp.351-366 (1986).

A. W. Castleman, Jr. and R. G. Keesee, "Ionic Clusters", Chem. Rev. 86, 589-618 (1986).

A. W. Castleman, Jr. and R. G. Keesee, "Clusters: Bridging the Gas and Condensed Phases", Accts. Chem. Res. 19, 413-419 (1986).

A. W. Castleman, Jr. and R. G. Keesee, "Clusters: Properties and Formation", Ann. Rev. Phys. Chem. 37, 525-550 (1986).

A. W. Castleman, Jr. and R. G. Keesee, "Metallic Ions and Clusters: Formation, Energetics, and Reaction", Z. Physik D 3, 167-176 (1986).

A. W. Castleman, Jr., C. R. Albertoni, K. O. Marti, D. E. Hunton, and R. G. Keesee, "Photodissociation of Negative Ions and Their Clusters", Farad. Discuss. Chem. Soc. 82, 261-273 (1986).

A. W. Castleman, Jr. and R. G. Keesee, "Dynamics of Dissociation and Reactions of Cluster Ions" in Structure/Reactivity and Thermochemistry of Ions, P. Ausloos and S. Lias, Eds., NATO ASI Series C 193, 185-217 (1987).

R. J. Shul, B. L. Upschulte, R. Passarella, R. G. Keesee, and A. W. Castleman, Jr., "Thermal Energy Charge Transfer Reactions of Ar+ and Ar2+", J. Phys. Chem. 91, 2556-2562 (1987).

R. G. Keesee, K. J. Kilgore, J. J. Breen, and A. W. Castleman, Jr., "The Formation of Clusters with Reactive Species: Precursors to Aerosol Formation in the Ammonia-Sulfur Dioxide System", Aerosol Sci. Technol. 6, 71-77 (1987).

B. L. Upschulte, R. J. Shul, R. Passarella, R. G. Keesee, and A. W. Castleman, Jr., "Diagnostics of Flow Tube Techniques for Ion-Molecule Reactions", Int. J. Mass Spectrom. Ion Proc. 75, 27-45 (1987).

R. G. Keesee and A. W. Castleman, Jr., "Acid Clusters" in The Chemistry of Acid Rain, R. W. Johnson and G. E. Gordon, Eds., ACS Symposium Series 349, ACS Books, Washington, DC, pp. 317-323 (1987).

R. J. Shul, B. L. Upschulte, R. Passarella, R G. Keesee, and A. W. Castleman, Jr., "Thermal Energy Reactions Involving Ar+ Monomer and Dimer with N2, H2, Xe, and Kr", J. Chem. Phys. 86, 4446-4451 (1987).

A. W. Castleman, Jr., S. W. Sigsworth, R. E. Leuchtner, K. G. Weil, and R. G. Keesee, "Considerations of the Rates and Lifetimes of Intermediate Complexes for the Association of Various Ligands to Metal Ions: Ag+ and Cu+", J. Chem. Phys. 86, 3829-3835 (1987).

D. H. Evans, R. G. Keesee, and A. W. Castleman, Jr., "The Association of Ammonia with Halide Ions in the Gas Phase", J. Chem. Phys. 86, 2927-2931 (1987).

A. W. Castleman, Jr., P. D. Dao, S. Morgan, and R. G. Keesee, " Resonance Enhanced Ionization of Clusters: Spectroscopy and Dynamics" in Resonance Ionization Spectroscopy 1986, Institute of Physics Conference Series 84, 209-216 (1987).

A. W. Castleman, Jr. and R. G. Keesee, "Cluster Spectroscopy: Variations in Ionization Potentials and Spectral Shifts as a Function of Degree of Aggregation and Studies of Cluster Fragmentation" in Physics and Chemistry of Small Clusters, P. Jena, B. K. Rao, and S. N. Khanna, Eds., NATO ASI Series B 158, 565-582 (1987).

R. G. Keesee, D. H. Evans, and A. W. Castleman, Jr., "The Thermodynamics of Mixed Solvent Cluster Ions: K+(CH3OH)n(H2O)m" in Physics and Chemistry of Small Clusters, P. Jena, B. K. Rao, and S. N. Khanna, Eds., NATO ASI Series B 158, 687-691 (1987).

R. J. Shul, R. Passarella, X. L. Yang, R. G. Keesee, and A. W. Castleman, Jr., "Studies of the Energy Dependence of Reactions of Ar+ and Ar2+ with CH4 and CS2", J. Chem. Phys. 87, 1630-1636 (1987).

R. Passarella, R. J. Shul, R. G. Keesee, and A. W. Castleman, Jr., "Gas Phase Reactions of Sulfides, Mercaptans, and Dimethyl Methylphosphonate with Ionic Species Derived from Argon and Water", Int. J. Mass Spectrom. Ion Proc. 81, 227-233 (1987).

W. J. Borucki, Z. Levin, R. C. Whitten, R. G. Keesee, L. A. Capone, A. L. Summers, O. B. Toon, and J. Dubach, "Predictions of the Electrical Conductivity and Charging of the Aerosols in Titan's Atmosphere", Icarus 72, 604-622 (1987).

R. G. Keesee and A. W. Castleman, Jr., "Monomeric Metaphosphate: Does it Exist in Aqueous Solution?", Z. Naturforsch. 42b, 1585-1587 (1987).

R. J. Shul, R. Passarella, L. T. DiFazio, Jr., R. G. Keesee, and A. W. Castleman, Jr., "Ion-Molecule Reactions Involving H3O+, H2O+, and OH+ at Thermal Energy", J. Phys. Chem. 92, 4947-4951 (1988).

B. L. Upschulte, R. J. Shul, R. Passarella, R. G. Keesee, and A. W. Castleman, Jr., "Curvature in the Plots for the Determination of Rate Constants from Fast-Flow Techniques", Int. J. Mass Spectrom. Ion Proc. 85, 277-285 (1988).

A. W. Castleman, Jr. and R. G. Keesee, "Clusters: Ionization, Reactions and Properties" in Elemental and Molecular Clusters in Materials Science, G. Benedek, T. P. Martin, and G. Pacchioni, Eds., Springer-Verlag, Berlin, pp. 307-328 (1988).

A. W. Castleman, Jr. and R. G. Keesee, "Gas Phase Clusters: Spanning the States of Matter", Science 241, 36-42 (1988).

E. E. Ferguson, C. R. Albertoni, R. Kuhn, Z. Y. Chen, R. G. Keesee, and A. W. Castleman, Jr., "The Role of Rotational Tunneling in the Metastable Decay of Rare Gas Cluster Ions", J. Chem. Phys. 88, 6335-6340 (1988).

S. W. Sigsworth, R. G. Keesee, and A. W. Castleman, Jr., "Appearance Potentials of CnH2n+2N+ Ions", J. Am. Chem. Soc. 110, 6682-6684 (1988).

A. W. Castleman, Jr. and R. G. Keesee, "Multiphoton Ionization of Clusters: Reactions and Spectroscopy" in The Structure of Small Molecules and Ions, R. Naaman and Z. Voger, Eds., Plenum Press, New York, pp. 133-145 (1988).
J. J. Breen, W.-B. Tzeng, R. G. Keesee, and A. W. Castleman, Jr., "Spectroscopy of Phenylacetylene-Carbon Dioxide Clusters", Chem. Phys. Lett. 150, 231-234 (1988).

R. G. Keesee and A. W. Castleman, Jr., "The Properties of Organic Compounds in Molecular Clusters", Aerosol Sci. Technol. 10, 352-357 (1989).

R. G. Keesee, "Nucleation and Particle Formation in the Upper Atmosphere", J. Geophys. Res. 94, 14683-14692 (1989).

J. J. Breen, K. Kilgore, S. Wei, W.-B. Tzeng, R. G. Keesee, and A. W. Castleman, Jr., "Spectroscopy of Phenylacetylene Bound to Clusters of Ammonia and the Surface Cluster Analogy", J. Chem. Phys. 90, 11-18 (1989).

J. J. Breen, W.-B. Tzeng, R. G. Keesee, and A. W. Castleman, Jr., "Intracluster Reactions in Phenylacetylene Ammonia Clusters Initiated Through Resonant Enhanced Ionization", J. Chem. Phys. 90, 19-24 (1989).

J. J. Breen, K. Kilgore, S. Wei, W.-B. Tzeng, R. G. Keesee, and A. W. Castleman, Jr., "Reactions of Hydrogen Halides with Clusters of Ammonia Molecules", J. Phys. Chem. 93, 7703-7707 (1989).

S. Morgan, R. G. Keesee, and A. W. Castleman, Jr., "Reactions of Methanol Clusters Following Multiphoton Ionization", J. Am. Chem. Soc. 111, 3841-3845 (1989).

R. G. Keesee and A. W. Castleman, Jr., "Structure of Solvated Cluster Ions" in Ion and Cluster Spectroscopy and Structure, J. Maier, Ed., Elsevier Science, Amsterdam, pp. 275-327 (1989).

K. L. Gleim, B. C. Guo, R. G. Keesee, and A. W. Castleman, Jr., "Thermodynamics for the Clustering of Ammonia onto Pb+ in the Gas Phase", J. Phys. Chem. 93, 6805-6809 (1989).

R. G. Keesee and A. W. Castleman, Jr., "The Hydration of Monomeric Metaphosphate Anion in the Gas Phase", J. Am. Chem. Soc. 111, 9015-9018 (1989).

R. G. Keesee and A. W. Castleman, Jr., "Photoabsorption and Photoionization of Clusters" in Atomic and Molecular Clusters, Studies in Physical and Theoretical Chemistry 68, E. R. Bernstein, Ed., Elsevier Science, Amsterdam, pp. 507-550 (1990).

R. Passarella, X. Yang, R. G. Keesee, and A. W. Castleman, Jr., "The Energy Dependence of the Reaction of N2+ with CS2", Int. J. Mass Spectrom. Ion Proc. 97, 125-130 (1990).

W. B. Tzeng, S. Wei, D. W. Neyer, R. G. Keesee, and A. W. Castleman, Jr., "Ammonia-Acetone Mixed Clusters: Internal Ion-Molecule Reactions, Structure, and Bonding", J. Am. Chem. Soc. 112, 4097-4104 (1990).

D. H. Evans, R. G. Keesee, and A. W. Castleman, Jr., "The Thermodynamics of Gas-Phase Mixed Solvent Cluster Ions: Water and Methanol on K+ and Cl- and Comparison to Liquid Solutions", J. Phys. Chem. 95, 3558-3564 (1991).

S. Wei, W. B. Tzeng, R. G. Keesee, and A. W. Castleman, Jr., "Metastable Unimolecular and Collision-Induced Dissociation of Hydrogen-Bonded Clusters: Evidence for Intracluster Molecular Rearrangement and the Structure of Solvated Protonated Complexes", J. Am. Chem. Soc. 113, 1960-1969 (1991).

R. G. Keesee, "Overview of the Atmospheric Chemistry Report" in U. S. National Report to International Union of Geology and Geophysics 1987-1990, Rev. Geophys., Supplement, p. 1 (1991).

R. W. Farley, P. J. Ziemann, R. G. Keesee, and A. W. Castleman, Jr., "Kinetic Study of Neutral Lead Cluster Reactions", Z. Phys. D 25, 267-273 (1993).

R. G. Keesee, B. Chen, A. C. Harms, and A. W. Castleman, Jr., "Reactions of Metal Oxide Anions", Int. J. Mass Spectrom. Ion Proc. 123, 225-231 (1993).

R. G. Keesee, "Experimental Approaches for Study of Atmospheric Aerosol Chemistry", (invited review), Trends in Geophys. Res. 2, 377-395 (1993).

R.G. Keesee, Book Review: Cluster Ions. Wiley Series in Ion Chemistry and Physics, J. Amer. Chem. Soc. 116, 11207-11208 (1994).

O. Sharoichenko and R.G. Keesee, "Numerical Analysis of the Vertical Motion of a Single Micron-Sized Particle in a Thermal Gradient Diffusion Chamber with Electrostatic Levitation", Aer. Sci. & Technol. 30, 320-331 (1999).

O. V. Hogrefe and R. G. Keesee, “Heterogeneous Vapor-to-Liquid Nucleation of Water on Individual Glass Particles”, Aer. Sci. & Technol. 36, 239-247 (2002).