Evaluating Experiment with Computation in Physical Chemistry: The Particle-In-A-Box Model with Cyanine Dyes

The results from a classic experiment in the undergraduate physical chemistry laboratory, the particle-in-a-box model for spectroscopic transitions of conjugated dyes, is compared to computational results obtained using a molecular mechanics structural approach and the extended Hückel molecular orbital picture. The goal of this exercise is to help students to think critically about their experimental data and to use comparisons of mathematical and computational models to try to understand departures of an experiment from expectations.