Research

Chemistry at interfaces

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.

Faculty Research Presentation

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

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

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

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

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)

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)

STM Imaging acquired by a student at Pacific University

Low Resolution Air Oxidation of GalenaSTM Measure of air oxidation of Galena

Galena OxidationHigh Resolution 2 hour oxidation of Galena

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)