Saturday, June 9, 2018

Summer research with Marmorino


No goggles for these students. Chemistry majors Conor McGee and Christian Moreno are spending the summer working on quantum mechanical problems with Professor Matt Marmorino. Their work is a combination of theory and computation - not a single chemical will be harmed in their research. Instead they'll be making good use of Mathematica to run number-crunching programs that they are very busy writing.

McGee is funded by the Carolyn & Lawrence Garber Summer Research Scholarship which is awarded each summer to just one chemistry or biochemistry major. He is testing (on the hydrogen atom) some old, but underutilized, techniques to calculate bounds to the energy and position moments for atoms and molecules. These techniques require information that is typically not available for traditional trial wave functions, but Conor is introducing an adjustable defect into the wave functions that, while reducing the quality of the wave function, allows for atypical information about the system to be calculated and utilized. If the approach works well on the hydrogen atom, then it should also work on more complex atoms and molecules too.

Moreno's work  is supported by one of several Louis Stokes Alliances for Minority Participation  (LSAMP) grants provided to STEM students at IU South Bend. He is testing simple quantum mechanical models to duplicate the known trends (such as atomic radius, ionization energy, and ground-state electron configuration) in the periodic table. The hydrogenic model, which ignores electron-electron repulsion is too simple to reproduce the trends; but the commonly-used Hartree-Fock method, which incorporates repulsion, is too complex for the beginning science student to fully appreciate and lacks a [rigorous] simple orbital interpretation.  Moreno is testing a model based on first-order perturbation theory that partly mimics the hydrogen model in simplicity, but incorporates at least some of the repulsion to reproduce the periodic trends. He's hoping that he doesn't need to deal with the repulsion in its full glory, because that is quite a task.