Abstract:

In this study, a computational chemistry exploration experiment for senior undergraduate or beginning graduate students is designed. The rotational isomerization reaction of an allyl cation is investigated using density functional theory (DFT) calculations. The theoretical experiment involves molecular geometry optimization, transition state location, and establishment of intrinsic reaction coordinates (IRCs). This design can help students understand the basic concepts and operations of computational chemistry. Furthermore, the concepts of molecular microstructures and the notion of "old bonds are about to break and new bonds are about to form" in the transition state theory are discussed. This experiment will also aid the understanding of the differences between reaction thermodynamics and kinetics through the construction of potential energy surfaces. Further investigations of charge population analysis and frontier orbital analysis will aid the understanding of electronic structures of molecules as well as the concept of reaction reactive sites.

Key words: Allyl cation, Rotational isomerism, Density functional theory, Potential energy surface, Experimental design