Laboratory Fellow, Physicist
Laboratory Fellow, Physicist


Dr. Greg Kimmel uses surface science techniques to investigate thermal and non-thermal reactions at surfaces and interfaces. These reactions are important in a wide range of applications, including catalysis, photocatalysis, radiation chemistry, and waste processing. The presence of surfaces or interfaces modifies the reactions and processes compared to what occurs in the bulk. However, a detailed understanding of the underlying physical and chemical processes at interfaces is often lacking. Because aqueous interfaces are important for many disciplines, the structure and reactivity of water at interfaces have been at the center of much of his research.  More recently, he has developed new experimental techniques that enable investigations into the properties of deeply supercooled water in a previously inaccessible temperature range.

Research Interest

  • the structure of water at interfaces
  • the properties of supercooled water
  • chemistry on oxide surfaces
  • energetic processes at surfaces and interfaces in fields such as radiation chemistry, waste processing, and advanced materials synthesis.


PhD in Applied Physics, Cornell University, 1992

BS in Engineering Physics, Cornell University, 1984

Affiliations and Professional Service

  • American Physical Society
  • American Chemical Society
  • American Vacuum Society

Awards and Recognitions



  • Kringle L.M., W.A. Thornley, B.D. Kay, and G.A. Kimmel. 2022. "Isotope effects on the structural transformation and relaxation of deeply supercooled water." The Journal of Chemical Physics 156(8):084501. PNNL-SA-168415. doi:10.1063/5.0078796
  • Lili L., J. Chun, X. Zhang, M. Sassi, A.G. Stack, C.I. Pearce, S.B. Clark, K.M. Rosso, J.J. De Yoreo, and G.A. Kimmel. 2022. “Radiolysis and Radiation-Driven Dynamics of Boehmite Dissolution Observed by In Situ Liquid-Phase TEM.” Environmental Science and Technology 56:5029−5036. (DOI: 10.1021/acs.est.1c08415)


  • Kringle L.M., W.A. Thornley, B.D. Kay, and G.A. Kimmel. 2021. "Structural relaxation and crystallization in supercooled water from 170 to 260 K." Proceedings of the National Academy of Sciences (PNAS) 118(14):e2022884118. PNNL-SA-158074. doi:10.1073/pnas.2022884118
  • Petrik N.G., Y. Wang, B. Wen, Y. Wu, R. Ma, A.P. Dahal, and F. Gao, et al. 2021. "Conversion of Formic Acid on Single- and Nano-Crystalline Anatase TiO2(101)." Journal of Physical Chemistry C 125(14):7686-7700. PNNL-SA-159116. doi:10.1021/acs.jpcc.1c00571
  • Riechers S.L., N.G. Petrik, J.S. Loring, M.E. Bowden, J.B. Cliff, M.K. Murphy, and C.I. Pearce, et al. 2021. "Direct Visualization of Radiation-Induced Transformations at Alkali Halide-Air Interfaces." Communications Chemistry 4(1): 49. PNNL-SA-155542. doi:10.1038/s42004-021-00486-2
  • Riechers S.L., N.G. Petrik, J.S. Loring, M.K. Murphy, C.I. Pearce, G.A. Kimmel, and K.M. Rosso. 2021. "Integrated Atomic Force Microscopy and X-ray Irradiation for In-situ Characterization of Radiation-Induced Processes." Review of Scientific Instruments 92(11):113701. PNNL-SA-161333. doi:10.1063/5.0054646


  • Deskins N.A., G.A. Kimmel, and N.G. Petrik. 2020. "Observation of molecular hydrogen produced from bridging hydroxyls on anatase TiO2(101)." The Journal of Physical Chemistry Letters 11(21):9289-9297. PNNL-SA-155933. doi:10.1021/acs.jpclett.0c02735
  • Kringle L.M., W.A. Thornley, B.D. Kay, and G.A. Kimmel. 2020. "Reversible structural transformations in supercooled liquid water from 135 to 245 K." Science 369(6510):1490-1492. PNNL-SA-150044. doi:10.1126/science.abb7542
  • Wang Y., B. Wen, A.P. Dahal, G.A. Kimmel, R.J. Rousseau, A. Selloni, and N.G. Petrik, et al. 2020. "Binding of Formic Acid on Anatase TiO2(101)." Journal of Physical Chemistry C 124(37):20228-20239. PNNL-SA-153864. doi:10.1021/acs.jpcc.0c06031


  • Petrik N.G. and G.A. Kimmel. 2018. "Electron-stimulated reactions in nanoscale water films adsorbed on (alpha)-Al2O3(0001)." Physical Chemistry Chemical Physics 20(17):11634-11642. PNNL-SA-132648. doi:10.1039/C8CP01284A
  • Petrik N.G., P.I. Huestis, J. Laverne, A. Aleksandrov, T.M. Orlando, and G.A. Kimmel. 2018. "Molecular water adsorption and reactions on (alpha)-Al2O3(0001) and (alpha)-Alumina Particles." Journal of Physical Chemistry C 122(17):9540-9551. PNNL-SA-132650. doi:10.1021/acs.jpcc.8b01969
  • Petrik N.G., R. Mu, A.P. Dahal, Z. Wang, A.I. Lyubinetsky, and G.A. Kimmel. 2018. "Diffusion and photon-stimulated desorption of CO on TiO2(110)." Journal of Physical Chemistry C 122(27):15382-15389. PNNL-SA-133615. doi:10.1021/acs.jpcc.8b03418
  • Zhang X., P.I. Huestis, C.I. Pearce, J.Z. Hu, K. Page, L.M. Anovitz, and A. Aleksandrov, et al. 2018. "Boehmite and Gibbsite Nanoplates for the Synthesis of Advanced Alumina Products." ACS Applied Nano Material 1(12):7115-7128. PNNL-SA-139693. doi:10.1021/acsanm.8b01969


  • Mu R., A.P. Dahal, Z. Wang, Z. Dohnalek, G.A. Kimmel, N.G. Petrik, and I.V. Lyubinetsky. 2017. "Adsorption and Photodesorption of CO from Charged Point-Defects on TiO2(110)." The Journal of Physical Chemistry Letters 8(18):4565-4572. PNNL-SA-128233. doi:10.1021/acs.jpclett.7b02052


  • Petrik N.G., G.A. Kimmel, M. Shen, and M.A. Henderson. 2016. "Quenching of Electron Transfer Reactions through Coadsorption: A Study of Oxygen Photodesorption from TiO2(110)." Surface Science 652. PNNL-SA-114433. doi:10.1016/j.susc.2015.12.038


  • Petrik N.G., and G.A. Kimmel. 2015. "Reaction Kinetics of Water Molecules with Oxygen Vacancies on Rutile TiO2(110)." Journal of Physical Chemistry C 119(40):23059-23067. PNNL-SA-111828. doi:10.1021/acs.jpcc.5b07526
  • Petrik N.G., M.A. Henderson, and G.A. Kimmel. 2015. "Insights into Acetone Photochemistry on Rutile TiO2(110). 1. Off-Normal CH3 Ejection from Acetone Diolate." Journal of Physical Chemistry C 119(22):12262-12272. PNNL-SA-108620. doi:10.1021/acs.jpcc.5b02477
  • Petrik N.G., M.A. Henderson, and G.A. Kimmel. 2015. "Insights into Acetone Photochemistry on Rutile TiO2(110). 2. New Photodesorption Channel with CH3 Ejection along the Surface Normal." Journal of Physical Chemistry C 119(22):12273-12282. PNNL-SA-108621. doi:10.1021/acs.jpcc.5b02478
  • Yoon Y., Y. Du, J.C. Garcia, Z. Zhu, Z. Wang, N.G. Petrik, and G.A. Kimmel, et al. 2015. "Anticorrelation between Surface and Subsurface Point Defects and the Impact on the Redox Chemistry of TiO2(110)." ChemPhysChem 16(2):313-321. PNNL-SA-105906. doi:10.1002/cphc.201402599


  • Lercher J.A., A.M. Appel, T. Autrey, R.M. Bullock, D.M. Camaioni, H.M. Cho, and D.A. Dixon, et al. 2014. "Multifunctional Catalysts to Synthesize and Utilize Energy Carriers." In Frontiers at the Interface between Homogeneous and Heterogeneous Catalysis, II, 207-219. Washington, District Of Columbia:U.S. Department of Energy, Office of Science. PNNL-SA-103068.
  • Petrik N.G., and G.A. Kimmel. 2014. "Probing the photochemistry of chemisorbed oxygen on TiO2(110) with Kr and other co-adsorbates." Physical Chemistry Chemical Physics 16(6):2338-2346. PNNL-SA-98647. doi:10.1039/c3cp54195a
  • Petrik N.G., R.J. Monckton, S. Koehler, and G.A. Kimmel. 2014. "Distance-dependent radiation chemistry: Oxidation versus hydrogenation of CO in electron-irradiated H2O/CO/H2O ices." Journal of Physical Chemistry C 118(47):27483-27492. PNNL-SA-105600. doi:10.1021/jp509785d
  • Petrik N.G., R.J. Monckton, S. Koehler, and G.A. Kimmel. 2014. "Electron-stimulated reactions in layered CO/H2O films: Hydrogen atom diffusion and the sequential hydrogenation of CO to methanol." Journal of Chemical Physics 140(20): 204710. PNNL-SA-100690. doi:10.1063/1.4878658


  • Petrik N.G., and G.A. Kimmel. 2013. "Multiple Non-Thermal Reaction Steps for the Photooxidation CO to CO2 on Reduced TiO2(110)." The Journal of Physical Chemistry Letters 4(3):344-349. PNNL-SA-92421. doi:10.1021/jz302012j


  • Du Y., N.G. Petrik, N.A. Deskins, Z. Wang, M.A. Henderson, G.A. Kimmel, and I. Lyubinetsky. 2012. "Hydrogen Reactivity on Highly-hydroxylated TiO2(110) Surfaces Prepared via Carboxylic Acid Adsorption and Photolysis." Physical Chemistry Chemical Physics. PCCP 14(9):3066-3074. PNNL-SA-82616. doi:10.1039/C1CP22515D
  • Kimmel G.A., M.D. Baer, N.G. Petrik, J. VandeVondele, R.J. Rousseau, and C.J. Mundy. 2012. "Polarization- and Azimuth-Resolved Infrared Spectroscopy of Water on TiO2(110): Anisotropy and the Hydrogen-Bonding Network." The Journal of Physical Chemistry Letters 3(6):778-784. PNNL-SA-85286. doi:10.1021/jz3001079
  • Lin X., Y. Yoon, N.G. Petrik, Z. Li, Z. Wang, V.A. Glezakou, and B.D. Kay, et al. 2012. "Structure and Dynamics of CO2 on Rutile TiO2(110)-1x1." Journal of Physical Chemistry C 116(50):26322-26334. PNNL-SA-89052. doi:10.1021/jp308061j
  • Petrik N.G., and G.A. Kimmel. 2012. "Adsorption geometry of CO versus coverage on TiO2(110) from s- and p-polarized infrared spectroscopy." The Journal of Physical Chemistry Letters 3(23):3425-3430. PNNL-SA-90608. doi:10.1021/jz301413v


  • Petrik N.G. and G.A. Kimmel. 2011. "Electron- and hole-mediated reactions in UV -irradiated O2 adsorbed on reduced rutile TiO2(110)." Journal of Physical Chemistry C 115(1):152-164. PNNL-SA-71556. doi:10.1021/jp108909p
  • Petrik N.G. and G.A. Kimmel. 2011. "Oxygen Photochemistry on TiO2(110): Recyclable, Photoactive Oxygen Produced by Annealing Adsorbed O2." The Journal of Physical Chemistry Letters 2(21):2790-2796. PNNL-SA-82849. doi:10.1021/jz201225c


  • Petrik N.G. and G.A. Kimmel. 2010. "Off-normal CO2 desorption from the photooxidation of CO on reduced TiO2(110)." The Journal of Physical Chemistry Letters 1(17):2508-2513. PNNL-SA-73722. doi:10.1021/jz100884w
  • Petrik N.G., and G.A. Kimmel. 2010. "Photoinduced Dissociation of O2 on Rutile TiO2(110)." The Journal of Physical Chemistry Letters 1(12):1758-1762. PNNL-SA-72411. doi:10.1021/jz100513e


  • Akin M.C., N.G. Petrik, and G.A. Kimmel. 2009. "Electron-Stimulated Reactions and O-2 Production in Methanol-Covered Amorphous Solid Water Films." Journal of Chemical Physics 130(10):104710. PNNL-SA-62554.
  • Petrik N.G. and G.A. Kimmel. 2009. "Nonthermal Water Splitting on Rutile TiO2: Electron-Stimulated Production of H-2 and O-2 in Amorphous Solid Water Films on TiO2(110)." Journal of Physical Chemistry C 113(11):4451-4460. PNNL-SA-60869.
  • Petrik N.G., Z. Zhang, Y. Du, Z. Dohnalek, I. Lyubinetsky, and G.A. Kimmel. 2009. "Chemical Reactivity of Reduced TiO2(110): The dominant role of surface defects in oxygen chemisorption." Journal of Physical Chemistry C 113(28):12407-12411. PNNL-SA-65119. doi:10.1021/jp901989x
  • Zhang Z., Y. Du, N.G. Petrik, G.A. Kimmel, I. Lyubinetsky, and Z. Dohnalek. 2009. "Water as a Catalyst: Imaging Reactions of O-2 with Partially and Fully Hydroxylated TiO2(110) Surfaces." Journal of Physical Chemistry C 113(5):1908-1916. PNNL-SA-62836.


  • Grieves G.A., N.G. Petrik, J. Herring-Captain, B. Olanrewaju, A. Aleksandrov, R.G. Tonkyn, and S.E. Barlow, et al. 2008. "Photoionization of Sodium Salt Solutions in a Liquid Jet." Journal of Physical Chemistry C 112(22):8359-8364. PNNL-SA-58466. doi:10.1021/jp7102534
  • Kimmel G.A. and N.G. Petrik. 2008. "Tetraoxygen on Reduced Ti02(110): Oxygen Adsorption and Reactions with Oxygen Vacancies." Physical Review Letters 100(19): 196102. PNNL-SA-58431. doi:10.1103/PhysRevLett.100.196102


  • Kimmel G.A., N.G. Petrik, Z. Dohnalek, and B.D. Kay. 2007. "Crystalline Ice Growth on Pt(111) and Pd(111): Nonwetting Growth on a Hydrophobic Water Monolayer." Journal of Chemical Physics 126(11): 114702. PNNL-SA-51889.
  • Lane C.D., N.G. Petrik, T.M. Orlando, and G.A. Kimmel. 2007. "Electron-Stimulated Oxidation of Thin Water Films Adsorbed on TiO2(110)." Journal of Physical Chemistry C 111(44):16319-16329. PNNL-SA-54544. doi:10.1021/jp072479o
  • Lane C.D., N.G. Petrik, T.M. Orlando, and G.A. Kimmel. 2007. "Site-Dependent Electron-Stimulated Reactions in Water Films on TiO2(110)." Journal of Chemical Physics 127(22): 224706. PNNL-SA-56026.
  • Petrik N.G., and G.A. Kimmel. 2007. "Hydrogen Bonding, H-D Exchange, and Molecular Mobility in Thin Water Films on TiO2(110)." Physical Review Letters 99(19): 196103. PNNL-SA-55179. doi:10.1103/PhysRevLett.99.196103


  • Kimmel G.A., N.G. Petrik, Z. Dohnalek, and B.D. Kay. 2006. "Layer-by-Layer Growth of Thin Amorphous Solid Water Films on Pt(111) and Pd(111)." Journal of Chemical Physics 125(4):044713-1 - 044713-12. PNNL-SA-48867. doi:10.1063/1.2218844
  • Petrik N.G., A.G. Kavetski, and G.A. Kimmel. 2006. "Electron-Stimulated Production of Molecular Oxygen in Amorphous Solid Water on Pt(111): Precursor Transport Through the Hydrogen Bonding Network." Journal of Chemical Physics 125(12):124702 (11 p.). PNNL-SA-50526.
  • Petrik N.G., A.G. Kavetski, and G.A. Kimmel. 2006. "Electron-Stimulated Production of Molecular Oxygen in Amorphous Solid Water." Journal of Physical Chemistry B 110(6):2723-2731. PNNL-SA-46633.


  • Garrett B.C., D.A. Dixon, D.M. Camaioni, D.M. Chipman, M.A. Johnson, C.D. Jonah, and G.A. Kimmel, et al. 2005. "Role of Water in Electron-Initiated Processes and Radical Chemistry: Issues and Scientific Advances." Chemical Reviews 105(1):355-389. PNNL-SA-42304. doi:10.1021/cr030453x
  • Kimmel G.A., N.G. Petrik, Z. Dohnalek, and B.D. Kay. 2005. "Crystalline Ice Growth on Pt(111): Observation of a Hydrophobic Water Monolayer." Physical Review Letters 95(16):166102. PNNL-SA-45342.
  • Lynch D.J., W.E. Wilson, M.T. Batdorf, M.B. Resat, G.A. Kimmel, and J.H. Miller. 2005. "Monte Carlo Simulation of the Spatial Distribution of Energy Deposition for an Electron Microbeam." Radiation Research 163(4):468-472. PNNL-SA-44733.
  • Petrik N.G. and G.A. Kimmel. 2005. "Electron-Stimulated Sputtering of Thin Amorphous Solid Water Films on Pt(111)." Journal of Chemical Physics 123(5):054702 (1-7). PNNL-SA-42923.
  • Petrik N.G. and G.A. Kimmel. 2005. "Low-Energy Electron-Stimulated Luminescence of Thin H20 and D20 Layers on Pt(111)." Journal of Physical Chemistry B 109(33):15835-15841. PNNL-SA-43848.
  • Sowa M.B., L.E. Kathmann, B.A. Holben, B.D. Thrall, and G.A. Kimmel. 2005. "Low-LET Microbeam Investigation of the Track-End Dependence of Electron-Induced Damage in Normal Human Diploid Fibroblasts." Radiation Research 164(5):677-679. PNNL-SA-42273. DOI: 10.1667/rr3464.1
  • Sowa M.B., M.K. Murphy, J.H. Miller, J.C. McDonald, D.J. Strom, and G.A. Kimmel. 2005. "A Variable-Energy Electron Microbeam: A Unique Modality for Targeted Low-LET Radiation." Radiation Research 164(5):695-700. PNNL-SA-40439. DOI: 10.1667/rr3463.1


  • Petrik N.G. and G.A. Kimmel. 2004. "Electron-Stimulated Production of Molecular Hydrogen at the Interfaces of Amorphous Solid Water Films on Pt(111)." Journal of Chemical Physics 121(8):3736-3744. PNNL-SA-41294.
  • Petrik N.G. and G.A. Kimmel. 2004. "Electron-Stimulated Reactions in Thin D2O Films on Pt(111) Mediated by Electron Trapping." Journal of Chemical Physics 121(8):3727-3735. PNNL-SA-41765.


  • Kimmel G.A., M. Persson, Z. Dohnalek, and B.D. Kay. 2003. "Temperature Independent Physisorption Kinetics and Adsorbate Layer Compression for Ar Adsorbed on Pt (111)." Journal of Chemical Physics 119(13):6776-6783. PNNL-SA-37480.
  • Petrik N.G. and G.A. Kimmel. 2003. ""Electron-Simulated Reactions at the Interfaces of Amorphous Solid Water Films Driven by Long-Range Energy Transfer from the Bulk". Physical Review Letters 90(16):166102. PNNL-SA-37444.


  • Sowa M.B., G.A. Kimmel, J.H. Miller, J.C. Mcdonald, M.K. Murphy, D.J. Strom, and B.D. Thrall, et al. 2002. "Spatially Resolved Single-Cell Irradiator to Study Bystander Responses to Low-LET Radiation." Radiation Research 158(3):375-376. PNNL-SA-40190.


  • Orlando T.M., G.A. Kimmel, and W.C. Simpson. 1999. "Quantum-Resolved Electron Stimulated Interface Reactions: D2 Formation from D2O Films." Nuclear Instruments and Methods in Physics Research. Section B, Beam Interactions with Materials and Atoms 157(1-4):183-190. PNNL-SA-31500.


  • Kimmel G.A., T.M. Orlando, P. Cloutier, and L. Sanche. 1997. "Low-Energy (5-40 eV) Electron-Stimulated Desorption of Atomic Hydrogen and Metastable Emission from Amorphous Ice." Journal of Physical Chemistry B 101(32):6301-6303. PNNL-SA-28046. doi:10.1021/jp9632091
  • Orlando T.M. and G.A. Kimmel. 1997. "The Role of Excitons and Substrate Temperature in Low-Energy (5-50 eV) Electron-Stimulated Dissociation of Amorphous D2O Ice." Surface Science 390(1-3):79-85. PNNL-SA-28659. doi:10.1016/S0039-6028(97)00511-6


  • Kimmel G.A. and T.M. Orlando. 1996. "Observation of Negative Ion Resonances in Amorphous Ice via Low-Energy (5-40 eV) Electron-Stimulated Production of Molecular Hydrogen." Physical Review Letters 77(19):3983-3986. PNNL-SA-27600. doi:10.1103/PhysRevLett.77.3983


  • Kimmel G.A. and T.M. Orlando. 1995. "Low-Energy (5-120 eV) Electron-Stimulated Dissociation of Amorphous D2O Ice: D(2S), O(3P2,1,0), and O(1D2) Yields and Velocity Distributions." Physical Review Letters 75(13):2606-2609. PNL-SA-26352. doi:10.1103/PhysRevLett.75.2606


  • Kimmel G.A., T.M. Orlando, C. Vezina, and L. Sanche. 1994. "Low-Energy Electron-Stimulated Production of Molecular Hydrogen from Amorphous Water Ice." Journal of Chemical Physics 101(4):3282-3286. PNL-SA-23672. doi:10.1063/1.468430