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Phillip Christiansen

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Phillip Christiansen
Associate Professor/Division Head
Chemistry & Biomolecular Science
245 Science Center
Clarkson University
PO Box 5810
Potsdam, NY 13699-5810
Phone: 315-268-2389

Educational Background
Ph.D., University of California at Santa Barbara

Research Interests
Much of our work has centered about the development of computational techniques for the determination of properties of molecules containing heavy elements. Our approach has been to extend the rigorous procedures employed in light element work to the lower rows of the periodic table by means of relativistic effective potentials. The potentials allow us to avoid the explicit treatment of "core" electrons in molecular calculations and to introduce relativity in a particularly convenient form. This work has included the development of nonconventional electron correlation treatments, specifically core-valence correlation formalisms and Quantum Monte Carlo. In Monte Carlo work, the use of effective potentials eliminates most of the singularity and node sampling in the vicinity of the nuclei and therefore leads to much smaller statistical errors. For a molecule with as few "d electrons" as Sc2, even quite extensive conventional studies give rather poor values for properties such as bond energies.

Finally, we have recently been working on the development of tools for accurately extending conventional quantum techniques to large biological and/or nano systems. Simple quantum capping potentials provide an effective means for partitioning the quantum and non-quantum regions in large scale molecular systems.

Selected Publications

  • S. Moon, P.A. Christiansen and G.A. DiLabio, "Quantum capping potentials with point charges: a simple QM/MM approach for the calculation of large-molecule NMB shielding tensors," J. Chem. Phys. 120, 9080 (2004).
  • G.A. DiLabio, M.M. Hurley and P.A. Christiansen, "Simple one-electron quantum capping potentials for use in hybrid QM/MM studies of biological molecules," J. Chem. Phys. 116, 9578 (2002).
  • P.A. Christiansen, "Basis Sets in Correlated Effective Potential Calculations," J. Chem. Phys. 111, 10070 (2000).
  • P.A. Christiansen, T.M. Moffett and G.A. DiLabio, "Potential Curves for the Mg+Rn Complex Including Charge-Transfer States," J. Phys. Chem. A103, 8875 (1999).
  • G.A. DiLabio and P.A. Christiansen, "Separability of Spin-orbit and Correlation Energies for the Sixth-row Main Group Hydride Ground States," J. Chem. Phys. 108, 7527 (1998).

Current Undergraduate Students

  • Courtney Grayson 2009, Biomolecular Science, Characterization of a simple transesterification reaction.
  • Graham Cullen 2005, Chemistry, Characterization of a simple transesterification reaction.