Matrix diagonalization, the key technique at the heart of modern computational chemistry for the numerical solution of the Schrödinger equation, can be easily introduced in the physical chemistry curriculum in a pedagogical context using simple Hückel molecular orbital theory for p bonding in molecules. We present details and results of computations, including both the quintessential examples of polycyclic aromatic hydrocarbons discussed in text books and an interesting extension to a large molecule, C[subscript 60] (buckminsterfullerene), the first member of the fullerenes to be discovered and synthesized, using a simple Excel spreadsheet-based VBA "application" that we have developed.