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Chemistry at interfaces
My primary research focus is the study atomic and molecular structure and reactivity at the interface between two phases.
My primary research focus is the study atomic and molecular structure and reactivity at the interface between two phases.
I have employed the experimental methods of Scanning Tunneling Microscopy, and Emersion IR spectroscopy. Currently my research efforts are focused on molecular dynamics simulations of interfaces.
I have also collaborated on studies of metal complexes using ab initio electronic structure computational methods.
Photoswitched Metal Organic Frameworks as Carbon Capture Materials
Photoswitched Metal Organic Frameworks as Carbon Capture Materials
Research with undergraduate students at Pacific University
switch_cube.webmWith a large ratio of internal surface area to mass and a high density of adsorption sites, porous Metal-Organic Framework (MOF) materials have the potential to be a practical means for CO2 capture. The structural variety of MOF materials synthesized using different metal vertices and organic linkers derived from a large library of components, and from post-synthetic modifications provides a rich opportunity to understand and ultimately design the local interactions of MOF interfaces with gaseous molecules.[i] One promising approach for CO2 capture utilizes MOF materials synthesized with photoswitch moieties incorporated in the linker molecules that can be used to control the kinetics of CO2 diffusion and reversible adsorption within MOF pores.[ii]
We propose to employ computational modeling of the molecular scale trajectories and energetics for CO2 transport through MOF materials containing photoswitch moieties. We hypothesize that an increased difference between diffusion rates for closed versus open photoswitch configurations can be achieved through selective chemical modifications to the photoswitch moieties.
[i] Yu, M.-H.; Geng, L.; Chang, Z.; Bu, X.-H. Coordination Bonding Directed Molecular Assembly toward Functional Metal–Organic Frameworks: From Structural Regulation to Properties Modulation. Acc. Mater. Res. 2023, 4 (10), 839–853. https://doi.org/10.1021/accountsmr.3c00097
[ii] Huang, Q.; Wu, C. Photoswitching Metal Organic Frameworks Development and Applications on Environmental Related Topics. Mater. Today Sustain. 2022, 18, 100149. https://doi.org/10.1016/j.mtsust.2022.100149
Faculty Research Presentation
Surfactants at the Oil / Water Interface
Surfactants at the Oil / Water Interface
Research with undergraduate students at Pacific University
Surfactants and other amphiphilic molecules present at the interface interact with both the aqueous and hydrophobic layers in a complex fashion that can dramatically change the characteristics of the interface as a whole. In this study, classical molecular dynamics computer simulations have been employed to investigate the accommodation of lauric acid at the water–hexane and water–carbon tetrachloride interfaces. Our results show that the behavior of surfactant molecules in the interfacial region is strongly influenced by the protonation of their headgroups.
Computational Modeling of Lauric Acid at the Organic–Water Interface; Lars K. Holte*, Bryan A. Kuran*, Geraldine L. Richmond, and Kevin E. Johnson. J. Phys. Chem. C, 118 (19), 10024 (2014).
https://doi.org/10.1021/jp411985c
Gaseous SO2 to aqueous SO2
Gaseous SO2 to aqueous SO2
Sabbatical Research at the University of Oregon, Chemistry Department, Geraldine Richmond Lab
Classical molecular dynamics have been employed in both equilibrium and steered molecular dynamics (SMD) simulations for SO2 at a neat-water surface and at a surface with high interfacial SO2 concentrations. The results provide new molecular insights for understanding the interaction of this prevalent gas on aerosols and other aqueous surfaces in the environment.
Dancing on Water: The Choreography of Sulfur Dioxide Adsorption to Aqueous Surfaces; Eric S. Shamay, Kevin E. Johnson, and Geraldine L. Richmond, J. Phys. Chem. C, 115 (51), 25304 (2011)
https://doi.org/10.1021/jp2064326
Simulations of Cytochrome P450 2A6
Simulations of Cytochrome P450 2A6
Collaboration with Jeannine Chan and John Harrelson. Pacific University
Video interview of Undergraduate Researcher Asela Chandrasinghe
Molecular dynamics was used to identify and characterize 'exit' paths for nicotine from the active site in Cytochrome P450 2A6.
Electronic structure Calculations of Nickel Complexes
Electronic structure Calculations of Nickel Complexes
I have collaborated with Eugene Urnezius at the University of Portland calculating electronic structure of metal complezes.
Complexes of Ni(II) with triphosphine-phosphite ligand P(OCH2PPh2)3: syntheses, structures, and electronic properties Aldona Beganskiene, Kevin E. Johnson, Nathan A. Phan*, Timothy J. Dobson*, Edward J. Valente, Eugenijus Urnezius Zeitschrift für anorganische und allgemeine Chemie 649, (2023) https://doi.org/10.1002/zaac.202300098
Bimetallic nickel complexes supported by 2,5-bis(phosphine)-1,4-hydroquinonate ligands. Structural, electrochemical and theoretical investigations; Pignotti, L. R., Luck, R. L., Deligonul, N., Protasiewicz, J. D., Johnson, K. E., Nguyen, L. P., and Urnezius, E. Inorganica Chimica Acta 424, 275 (2015). https://doi.org/10.1016/j.ica.2014.08.049
Infrared reflectance-absorbance spectroscopy of thin films formed by forced dewetting of solid-fluid interfaces
Infrared reflectance-absorbance spectroscopy of thin films formed by forced dewetting of solid-fluid interfaces
Sabbatical Research at the University of Arizona, Chemistry Department, Jeane Pemberton Lab
Infrared reflectance-absorbance spectroscopy of thin films formed by forced dewetting of solid-fluid interfaces; S.T. Heier, K.E. Johnson, A. Mudalige, D.J. Tiani, V.R. Reid*, J.E. Pemberton, Anal. Chem. 80, 8012 (2008). https://doi.org/10.1021/ac801019r
Atomic Sructure of Oxygen adsorbed on W(110)
Atomic Sructure of Oxygen adsorbed on W(110)
Work done as a postdoc at IBM Almaden Research Labs
Mentors: Shirley Chiang and Robert Wilson
Effects of adsorption site and surface stress on ordered structures of oxygen adsorbed on W(110); K.E. Johnson, R.J. Wilson, and S. Chiang, Phys. Rev. Lett., 71, 1055 (1993). https://doi.org/10.1103/PhysRevLett.71.1055
Air oxidation of Galena (PbS)
Air oxidation of Galena (PbS)
STM Imaging acquired by a student at Pacific University
Scanning Tunneling Microscopy
Scanning Tunneling Microscopy
Thesis Research at The University of Washington
Thomas Engel Mentor
The mesoscopic and microscopic consequences of decomposition and desorption of ultrathin oxide films from Si(100) studied by scanning tunneling microscopy; K.E. Johnson, P.K. Wu, M. Sander, and T. Engel, Surf. Sci., 290, 213 (1993). https://doi.org/10.1016/0039-6028(93)90705-O
Direct measurement of reaction kinetics for the decomposition of ultrathin oxide on Si(001) using scanning tunneling microscopy; K.E. Johnson and T. Engel, Phys. Rev. Lett., 69, 339 (1992). https://doi.org/10.1103/PhysRevLett.69.339
Scanning Tunneling Microscope image of Silver (115)
Scanning Tunneling Microscope image of Silicon (111)
Scanning Tunneling Microscope Image of Silicon (100)
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