Hello & Welcome!
I am a research scientist in the Physical Sciences Division of the Pacific Northwest National Laboratory (PNNL) in Richland WA. I specialize in molecular spectroscopy and am broadly interested in all aspects of experimental physical chemistry, including membrane biophysics. Prior to joining PNNL, I was an Assistant Professor in the Department of Chemistry at Temple University in Philadelphia. My research there was primarily focused on application and development of nonlinear laser light scattering and imaging methods (e.g., second-harmonic generation, SHG) as a means of quantifying molecular interactions at the surfaces and buried interfaces of colloidal objects, including living bacterial cells, micron-sized polymer beads, metallic nanoparticles, and aerosol particles. In general, my work focused on quantifying the thermodynamics of molecular surface adsorption and desorption of drug-like molecules from the membrane surfaces of living cells. Additionally, I developed SHG-based protocols for quantifying the kinetics of molecular transport across membranes in living cells. This approach was applied as a means of characterizing the mechanism-of-action of antimicrobial compounds (e.g., chemical-induced changes to membrane permeability, influence and activity of bacterial efflux pumps, activation of molecular importers), quantitative imaging of regional-specific membrane viscosity in living cells, characterization of temperature-induced membrane phase transitions in model and living cells, and even correcting / updating the previously accepted molecular mechanism of the well-known Gram-stain protocol for differentiating Gram-positive vs. Gram-negative bacteria.
In addition to using nonlinear optics to study the surface chemistry of colloidal objects, my research is also focused on application of time-resolved Fourier transform infrared (FTIR) emission spectroscopy to study vibrationally highly excited molecules. This includes quantification of the branching ratios and energy partitioning following UV photolysis reactions, ro-vibrational spectroscopy of radicals and short-lived molecular transients (e.g., HNC), and collisional deactivation of molecules containing chemically relevant amounts of energy. My recent efforts in this area have been on quantifying the branching ratio of the geometric isomers, hydrogen cyanide (HCN) and hydrogen isocyanide (HNC) following UV photolysis of cyano-containing molecules as a means of explaining the overabundance of astrophysical HNC.
If any of this resonates with you, you might just be in the right place! Either way, welcome in!
Cheers,
MJW
Philadelphia, PA
michael.wilhelm (at) alumni.upenn.edu
In addition to using nonlinear optics to study the surface chemistry of colloidal objects, my research is also focused on application of time-resolved Fourier transform infrared (FTIR) emission spectroscopy to study vibrationally highly excited molecules. This includes quantification of the branching ratios and energy partitioning following UV photolysis reactions, ro-vibrational spectroscopy of radicals and short-lived molecular transients (e.g., HNC), and collisional deactivation of molecules containing chemically relevant amounts of energy. My recent efforts in this area have been on quantifying the branching ratio of the geometric isomers, hydrogen cyanide (HCN) and hydrogen isocyanide (HNC) following UV photolysis of cyano-containing molecules as a means of explaining the overabundance of astrophysical HNC.
If any of this resonates with you, you might just be in the right place! Either way, welcome in!
Cheers,
MJW
Philadelphia, PA
michael.wilhelm (at) alumni.upenn.edu