Computational chemistry in the physical chemistry curriculum

 

Jonathan M. Smith

Department of Chemistry

Gustavus Adolphus College

Saint Peter, MN 56082

 

 

Molecular modeling has taken on an increasingly important role as a tool for chemists.  It is particularly important that undergraduates are cognizant of the strengths and shortcomings of these approaches.  The physical chemistry curriculum, integral to chemistry and many biochemistry majors, represents the ideal opportunity for students to examine many of the details of computational chemistry as part of an overall plan to integrate computational tools into students’ vernacular from the first year on.  Specific investigations focus on correlating computational results with experimental investigations, examining the quality of these results, and a deeper exploration of the underlying theory.  In a thermodynamics and kinetics course, the heats of combustions of a series of hydrocarbons are tabulated using semi-empirical calculations carried out in Hyperchem coupled to an Excel Visual Basic program and compared to subsequent bomb calorimetry.  Additionally, the barrier height for isomerization in N,N˘‑dimethylacetamide and related compounds is investigated computationally and using NMR spectroscopy.  Both of these investigations allow students to think critically about the quality of the computational and experimental data.  In a quantum chemistry course, ab initio calculations and evaluating the quality of these results as a function of basis set, method, and computational time are introduced and explored in the context of analysis of the rovibronic spectra of HCl.  As well, the idea of basis functions is explored by fitting Slater radial functions with Gaussians in Maple.  Interweaving computational and experimental approaches deepens the ability of students to develop chemical intuition by testing molecular hypotheses before and after carrying out experimental work.