Research

Catamaran Labs:

I am currently working to find research collaborators to design new experiments and more applications for the FTIR ATR instrument that I designed at Berkeley. I have founded a company in Boulder, CO, where I am continuing to re-design and optimize my instrument to make it easier to use and more robust.


I am looking to find collaborators in the following research:

  • Li+ Battery
  • Atomic Layer Deposition
  • Films/ Coatings
  • Surface Catalysis
  • Reverse Osmosis Membranes
  • Metal Organic Frameworks
  • Gas uptake/ Sequestration
  • Interstellar Ices



Postdoctoral Research:

I designed a novel Attenuated Total Reflectance (ATR) instrument that can be couple to many different light sources/detectors. It has already been demonstrated with a tunable IR laser system and more recently, a commercial Fourier Transform Infrared (FTIR) spectrometer (Thermo Fisher Nicolet 6700). Through the unique design of the instrument, optical access to the sample does not require blocking physical access and so in-situ reactions can be carried out while recording real time spectra. Temperature control via the back surface is also available. Silicon is an ideal substrate due to its chemical inertness, its temperature stability, and it's ubiquitous use in material science and industry settings.


Graduate Research:

In the Ellison lab, we look to better understand thermal decomposition in its simplest form, single precursor molecules undergoing unimolecular decay mechanisms in the first 100 microseconds of heating. By reducing the complexity of the systems, we can directly identify product channels and often conclude which pathways become active at lower temperatures.

To study these systems, we flow dilute mixtures of precursor molecules in He, Ne, or Ar carrier gas through a 1 mm inner diameter SiC reactor that can be resistively heated up to 1700 K. Recent computational modeling has provided significant insight into the temperature and pressure inside the reactor as a function of carrier gas, inlet pressure, downstream pressure, reactor temperature, and mass flow rate of gas. At the exit of the reactor, the gas is supersonically cooled to quench any further reactions and to prepare the thermal products for molecular detection. In the last 5 years, our group has used a set of complimentary diagnostics which include:

  1. Photoionization Mass Spectrometry (PIMS) using 118.2 nm (10.5 eV) to allow rapid detection of any gas phase products that have an ionization energy of 10.5 eV or less. This can performed at our labs in Boulder, CO and Golden, CO.
  2. PIMS with tunable synchrotron light (ALS in Berkeley, CA and SLS in Switzerland) which permit measurement
    • Threshold ionization energies to distinguish between isomers of the same mass-to-charge ratio
    • Ionization just above threshold to prevents fragmentation of molecules after irradiation.
  3. Matrix isolation Vibrational (IR) Spectroscopy in Neon and Argon, which provides direct identification of products in the form of vibrational spectra. If the spectrum of a molecule is already known it can be carefully assigned in our product spectra or if the spectra has never been measured before, we can often assign the vibrational peaks ourselves.
  4. Resonance Enhanced Multi-photon Ionization (REMPI) is a technique we use to identify individual molecules in our expansion by searching for their unique REMPI spectrum.
  5. Chirped pulse Fourier Transform Microwave Spectroscopy can been coupled to the reactor to directly measure the exact molecular geometry of product molecules. The bond lengths and bond angles of cyclopentadienone were measured using this technique

Since joining the group, I have used many of the above techniques to study the decomposition of benzyl radical, which was shown to decompose through multiple isomerization pathways rather than direct bond cleavage. The figure below shows a few of the potential mechanisms which are implicated as a result of multiple isotopically substituted benzyl radicals studied (C6H5-CH2, C6H5-CD2, C6D5-CH2, C6H5-13CH2).

For more detail, see our recent paper in The Journal of Chemical Physics