Olson Research Group

Olson Research Group

Sub–Molecular Tunneling Spectroscopy

RESEARCH

Primary Research Areas

A Note Regarding Undergraduate Research

As a philosophy, I am firmly dedicated to the incorporation of undergraduate researchers into my research program. This philosophy stems from my own experiences as an undergraduate research assistant. I found my time in undergraduate research to be enriching and fulfilling; it ultimately led to my pursuit of a doctorate degree in chemistry. Therefore, I would encourage any individual who is pursuing a B.S. in one of the sciences (or in engineering) to investigate undergraduate research. As far as my research projects are concerned, I have opportunities for research by undergraduate students in both my educational and STM microscopy projects. Also, my policy is to include undergraduate researchers, who have sufficiently contributed, to be listed as coauthors on any resulting publications.

Scanning Tunneling Microscopy of Molecular Monolayers of Pharmaceutical Candidates

 

Monolayer Image of 8-Fluorotryptanthrin

One primary area of the Olson Group's research involves utilizing scanning tunneling microscopy to investigate the sub-molecular geometric and electronic features of molecules of interest. The primary analyte for these studies is tryptanthrin and its analogs. Tryptanthrin is a known anti-parasitic agent, showing efficacy against pathogens that cause diseases such as malaria, lieshmania, and fungal infections, among others.  One interesting effect the group observed along the way is adsorption-induced stereoisomerization wherin otherwise achiral molecules become chiral upon adsorption to a graphite surface.  This is the first-ever report of physisorption-induced stereoisomerization in individual molecules.

Pertinent Publications

Sub-Molecular Barrier Height Tunneling Spectroscopy of Molecular Monolayers

DFT, Topographical, and Barrier images of a tryptanthrin analog

Barrier height tunneling spectroscopy is among the first types of tunneling spectrosocpy performed with STM on clean semiconductor and metal surfaces.  However, adding a molecular monolayer to a surface significantly increases the complexity of interpreting the barrier height data.  Our group has systematically approached this issue to de-convolute tunneling barrier height data.  Starting with more simplistic systems, we have identified three primary contributing factors to the features observed in tunneling barrier height maps, namely electrostatic contributions (via electron states of the substrate), molecular orbital contributions (via the mediating states of the molecule), and a ubiquitous topographical effect.

Pertinent Publications

Direct Analysis in Real Time (DART) Mass Spectrometry of Self-Assembled Monolayers

Depiction of DART-MS of a SAM

Early in the development of DART, our group investigated the use of this novel form of atmospheric ionization toward the analyses of self-assembled monolayers on gold surfaces.  Via this method, we were able to easily observe mass spectra from monolayers of material in nanogram amounts.  Furthermore, we observed that the ionized species from alkane thiols form dimers and trimers via sulfur–sulfur bonds.  The author list of the resulting publication includes Robert B. "Chip" Cody, the co–inventor of the DART ionization method.

Pertinent Publication

Nano–Chemistry Education

Representative images of educational projects

Dr. Olson is deeply committmed toward chemical education and the training of the next generation of scientists.  This committment is borne of his work with his doctoral advisor, Arthur B. Ellis.  To this end, the group has developed tools for educational enhancement, including nano–chemistry laboratory experiments, as well as the use of 3-D printing as a means of producing inexpensive, robust solid-state crystal models for use in a chemistry classroom.

Pertinent Links