Cheol Ho Choi

  Professor

  Ph.D., Georgetown Univ.

  Tel : +82-53-950-5332

  Fax : +82-53-950-6330

  E-mail : cchoi@knu.ac.kr

  Homepage : http://qchem.knu.ac.kr

 

  Research Interest

 

circle03_darkblue.gif Computational Quantum Chemistry: Surface Chemistry: Surface of solid state materials are chemically active due to the existence of under-coordinated atoms. An active surface is likely undergo relaxation and reconstruction in order to be stabilized. However, such processes are hindered by the latent structural resistance of sub-surface layers. Consequently, the chemistry on the surface is determined not only by the atoms of the surface but by their sub-surface layers as well. Due to the nature of surface, sometimes we would see unusual chemical reactions on surface. Recently, we have developed a new method, SIMOMM specifically for this kind of problems. We are interested in improving the method as well as its applications on real chemical systems. With the help of newly developed linear scaling quantum theories, nano-materials such as molecular materials, conducting polymers, dendrimers, fullerene derivatives, buckytubes, etc are being studied.

circle03_darkblue.gif  Theoretical Quantum Chemistry: Hybrid quantum mechanics/molecular mechanics (QM/MM) techniques have gained popularity for modeling large molecular systems. In this approach, one assumes that a large molecular system can be partitioned into a small, chemically active part where a reaction will occur, and a larger, chemically inactive piece. We are developing and improving SIMOMM (one kind of QM/MM adapted for the surface chemistry). Linear scaling quantum theories are very promising, which has the potential to overcome the traditional high-order scaling barrier.  We are currently developing QFMM(Quantum Fast Multipole Method), a linear scaling HF for the general use. We plan to develop linear or low-scaling post-HF theories in order to provide more accurate computations of nano-materials.

 

  Selected Publications

 

1. Cycloaddition reactions of Acrylonitrile on the Si(100)-2x1 surface, Choi, C. H.; Gordon, M. S. J. Am. Chem. Soc. 2002, 124, 6162.

2. Passive and Active Oxidation of Si(100) by Atomic Oxygen: A Theoretical Study of Possible Reaction Mechanisms Choi, C. H.; Liu, D.; Evans, J. W.; Gordon, M. S. J. Am. Chem. Soc. 2002, 124, 8730.

3. Chemistry on Silicon surfaces, Choi, C. H.; Gordon, M. S. "The Chemistry of Organic Silicon Compounds", Vol. 3 edited by Saul Patai and Zvi Rappoport, John Wily & Sons, 2001

4. A new parallel, optimal-parameter fast multipole method, Choi, C. H.; Ruedenberg, K.; Gordon, M. S. J. Comp. Chem. 2001, 22, 1484.

5. Rapid and Stable Determination of Rotation Matrices between Spherical Harmonics by Direct Recursion, Choi, C. H.; Ivanic, J.; Gordon, M. S.; Ruedenberg, K. J. Chem. Phys. 1999, 111, 8825.

6. Cycloaddition Reactions of 1,3-cyclo-hexadiene on Silicon (001) Surface, Choi, C. H.; Gordon, M. J. Am. Chem. Soc, 1999, 121, 11311.