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Chemistry - Faculty - Edwin Stevens

Dr. Edwin Stevens

Dr. Edwin Stevens

Scholar in Residence

Office:  TCCW 110B
Phone:  270-745-4681

Research

Physical

crystallography, x-ray structure determination, experimental electron distributions

When a small crystal is placed in a beam of x-rays, the scattered waves of photons will interfere with each other, creating a diffraction pattern.  Since the x-rays are scattered by the electrons in the crystal, the intensities of the diffracted x-rays carry information on the location of regions of high electron concentration (atoms) in the crystal.  Analysis of the data yields accurate determination of the location and motion of all of the atoms in the sample.  Thus, single crystal x-ray diffraction measurements allow us to “see” the structure of molecules at atomic resolution.  The experiment is more accurate than any other method of analysis, because we can determine the atom type and location of every atom in a chemical compound.  For synthetic chemists, a single crystal x-ray structure determination provides irrefutable evidence for the identity of a reaction product.  When applied to larger molecules of biological interest, such as proteins and enzymes, it allows us to elucidate the mechanisms of biochemical processes at atomic resolution, and it has become an essential tool in the design of new drugs.  These experiments are conducted at WKU using a state-of-the-art robotic instrument that positions the crystal and records the scattered x-ray photons under computer control.  In addition to determining the location of atoms, in my research program, we make very accurate measurements in order to obtain an accurate map of the distribution of electrons in the crystal in order to investigate the electronic structure of materials.

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 Last Modified 9/25/14