General

   Molecular structure studies

   Electronic structure studies

   Tools

We use a combination of experimental and computational methods to arrive at conclusions in our research. Calculations are employed either to explain experimental findings or to guide experiments. Depending on the state of the particular project, students can often choose a more experimental or a more computational focus.

Experimental tools

Most compounds of interest are not commercially available, and so have to be synthesized, isolated and purified. Compounds may be sensitive to moisture or oxygen, and so inert gas techniques might be necessary.

Apart from using the full range of common spectroscopic and spectrometric techniques to characterize reaction products, we use FTIR and NMR (¹H, ¹³C, ¹⁷O) spectroscopies to detect weak bonding interactions. FTIR and 300 and 500 MHz NMR spectrometers are readily available in the department. The recent arrival of a single-crystal X-ray diffractometer in the department now allows us to obtain crystal structures routinely, which will be of high value in hydrogen-bonding studies.

Flash pyrolysis is used for the thermolytic generation of reactive intermediates in the gas phase from suitable precursors.

Finally, electronic structures can be determined experimentally through ultraviolet photoelectron spectroscopy on molecules in the gas phase. These studies are done in collaboration with Prof. Nick Werstiuk at McMaster University.

Computational tools

The department houses the Centre for Research in Molecular Modeling (CERMM), which is where we perform most of our calculations. On occasion, we use supercomputers elsewhere in Canada, but CERMM clusters are equipped with most of what we need. Most of our computational work revolves around electronic structure calculations.

Studies start the usual way with geometry optimizations (minima, relaxed scans, transition states, intrinsic reaction coordinates) and frequency calculations. We then calculate properties as needed (molecular orbitals, spin densities, anharmonic frequencies, isotropic shieldings). Detailed analyses are carried out using NBO or NRT (natural bond orbitals or resonance theory) approaches. For molecular structure studies, we analyse the electron density within the framework of QTAIM (the quantum theory of atoms in molecules).

Last update: august10; hmm