I have implemented Student Molecule Projects in two of our Physical Chemistry courses that use trading cards I created (§10 includes a partial set of cards that can be downloaded). The students receive a randomized set of four cards that include two "backbone" cards that provide the core structure of their molecule as well as Hydrogen and Chlorine cards to be used to build a closed-shell molecule featuring their backbone.

The starting point of the project is to generate coupling diagrams for their molecules that follow various guidelines. To insure they are on the right track, I ask them to submit their coupling diagrams for approval and provide feedback as necessary. They may submit their coupling diagrams in freehand form or using PowerPoint templates that I provide to them (a template file may be downloaded in §10).

Once their coupling diagrams are approved, the students need to perform various tasks using either additional information I provide to them or that they calculate for themselves. This varies in the two courses and is summarized below.

For both courses, I am including screenshots of actual coupling diagrams from students, with freehand and template-based samples.

For this course, the students are given guidelines that lead them to produce molecules from a limited set for which I have previously run calculations of structure, rotational constants, and vibrational frequencies. The molecule project involves producing a coupling diagram for their molecule, describing its bonding, and identifying its symmetry point group. In addition, I provide the calculated properties for their molecules to them and ask them to calculate its partition function contributions and other quantities that can be derived from partition functions such as internal energy, constant volume heat capacity, and entropy.

For this course, the students are given guidelines that are more open-ended since they calculate the properties of their molecules themselves at the ChemCompute website (chemcompute.org). I provide sample input files they can modify and submit at the website. I ask them to report structural parameters and various properties as well as a screenshot of an orbital.

The next section describes the origins and use of coupling diagrams in the chemical literature.