Contact Information (Georg Schreckenbach)


|e-mail|  Georg Schreckenbach 
|phone| +1-(514) 848-3352
|fax| +1-(514) 848-2868 
|regular mail|
Department of Chemistry, University of Manitoba
Winnipeg, Manitoba, Canada, R3T 2N2
http://www.geocities.com/gschreckenbach/
 
To see a list of my publications and other works click here
To see my resume click   here

To see my web-page click   here
Copy of thesis here

Research Interests while in Calgary

I am interested in electronic structure calculations based on first principle quantum mechanics. This is an area of rapidly growing importance, both for academic and industrial research. It is also the general framework for the research of this group. In my Ph.D. studies, I have concentrated on method development and application of the newly developed computer programs. In particular, I have focused on static magnetic properties (NMR, ESR, etc.) and on relativistic effects.
The research of our group is based on density functional theory (DFT). DFT is increasingly being recognized and used as a reliable yet economic tool in computational chemistry. It is particularly powerful for the investigation of larger systems such as heavy element compounds, transition metal complexes, or materials in condensed phases.

During the last three years, I have applied the DFT methodology to the calculation of nuclear magnetic resonance (NMR) chemical shifts. DFT works well for systems ranging from simple hydrocarbons to heavy element compounds. As an example, we were able to calculate the 183W shift of W(CO)6 relative to [WO4]2- quantitatively: calculated -3,615 ppm; experimental -3,505 ppm (G. Schreckenbach, T. Ziegler, Int. J. Quantum Chem., in print). To calculate the NMR chemical shift (shielding), we used the so-called "gauge including atomic orbitals" (GIAO) method. As shown above by the example, we have extended this work to include (scalar) relativistic effects, thus opening, for the first time, the whole range of multinuclear NMR to theoretical investigations. To date, our program is the only first principle method that is capable of calculating heavy element chemical shifts.

As the last step of my Ph.D. research, I am currently working on an implementation to calculate the g-tensor of electron spin resonance (ESR) spectroscopy. The g-tensor and the NMR shielding are conceptually very similar from a theoretical point of view. Thus, the NMR program is readily extended to include the g-tensor as well.
Theoretical calculations of observed ESR g-values have so far only been possible based on semi-empirical methods. While such methods can be very successful, they are based on certain empirical parameters, and thus rely on a good knowledge of the given system. This is not the case for first principle methods. Therefore, various applications are conceivable.

Another logical extension of the NMR/ESR program would be the calculation of the magnetic susceptibility. Our common formulation of the different magnetic properties (NMR shifts, ESR g-tensor, susceptibility, etc.) has the advantage that all existing features of the NMR program (use of GIAO's, sophisticated analysis tools in terms of the molecular orbitals, relativistic extension, among others) are readily available for the various other properties.

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