Stephen G. Urquhart Associate Professor of Chemistry Associate Member, Department of Physics Physical and materials chemistry, Synchrotron chemistry B.Sc.(Hons.) McMaster University, 1992 Ph.D. McMaster University, 1997 Office: Thorvaldson 157 Phone: (306) 966-4657 Fax: (306) 966-4730 email: stephen.urquhart@usask.ca Group Web site

Graduate Student Positions Available - Chemistry and Physics
PhD Position Available - X-ray Microscopy of Strain in Semiconductor Materials

Research Interests:

• Materials Chemistry
  We use X-ray microscopy to study the structure and composition of complex, nanostructured materials, with an eye to understanding the thermodynamics and kinetics of nanostructure formation. Organic nanostructures are of particular interest, where we use epitaxy to control and pattern molecular orientation at microscopic length scales. We also study the embrittlement mechanisms in stainless steel alloys (in collaboration with Syncrude) and phase separated Langmuir Blodgett thin films (in collaboration with M. Paige, Chemistry)
  
• Molecular Spectroscopy
  The chemical sensitivity of Near Edge X-ray Absorption Fine Structure (NEXAFS) spectroscopy provides the exquisite sensitivity of x-ray microscopy for basic and applied materials chemistry analysis, particularly as it can provide detailed and quantitative chemical information at high spatial resolution (e.g. below 50 nm). My research combines experimental and computational studies to understand the structure - spectral relationships for organic molecules. These questions range from the practical to the esoteric, such as the nature of "matrix effects" in condensed molecules, orientation dependence in complex organic molecules, and the natural circular dichroism of chiral organic molecules at x-ray wavelengths.

Representative Publications:

1. S. Christensen, U.D. Lanke, B. Haines, S.G. Urquhart, S.E. Qaqish, M.F. Paige, S.G. Urquhart, Structural and compositional mapping of a phase-separated Langmuir-Blodgett monolayer by X-ray photoelectron emission microscopy, 2008 Journal of Electron Spectroscopy and Related Phenomena 162(3) 107-114.
2. S.G. Urquhart, U.D. Lanke, J. Fu, 2008, Characterisation of molecular orientation in organic nanornaterials by X-ray Linear Dichroism Microscopy, International Journal of Nanotechnology, 5(9-12) 1138-1170.
3. E. Otero, R.G. Wilkes, T. Regier, R.I.R. Blyth, A. Moewes, S.G. Urquhart, 2008 Substituent effects in the iron 2p and carbon 1s edge near-edge X-ray absorption fine structure (NEXAFS) spectroscopy of ferrocene compounds, Journal of Physical Chemistry A 112(4) 624-634.
4. J. Fu, S.G. Urquhart, 2007, Effect of chain length and substrate temperature on the growth and morphology of n-alkane thin films, Langmuir, 23, 2615-2622.
5. E. Otero, S.G. Urquhart, 2006, Nitrogen 1s near-edge X-ray absorption fine structure spectroscopy of amino acids: Resolving zwitterionic effects, Journal of Physical Chemistry A, 110, 12121-12128.
6. J. Fu, S.G. Urquhart, 2005, Linear dichroism the X-ray absorption spectra of linear n-alkanes, Journal of Physical Chemistry A, 109, 11724-11732.
7. S. G. Urquhart, R. Gillies, 2005, Rydberg-Valence Mixing in the Carbon 1s Near-Edge X-ray Absorption Fine Structure Spectra of Gaseous Alkanes. 2005. Journal of Physical Chemistry A 109, 2151-2159.
8. R.R. Cooney, S.G Urquhart, 2003, Chemical Trends in the Near-Edge X-ray Absorption Fine Structure of Monosubstituted and Para-Bisubstituted Benzenes,Journal of Physical Chemistry B, 108, 18185-18191.