Ab Initio Determinations of Photoelectron Spectra Including Vibronic Features. An Upper-Level Undergraduate Physical Chemistry Laboratory

Abstract

We present a first-principles determination of the photoelectron spectra of water and hypochlorous acid as a laboratory exercise accessible to students in an undergraduate physical chemistry course. This paper demonstrates the robustness and user-friendliness of software developed for the Franck–Condon factor calculation. While the calculator is suitable for determining multiple types of electronic spectra, the paper focuses on photoelectron work. Because it is based upon ionization, photoelectron spectroscopy is an intuitively satisfying electronic technique that offers undergraduate students a glimpse into the abstract and often confusing concept of vibronic structure. While experimental application of this method is both expensive and challenging, it is ideally suited to theoretical determination. The vibrational envelopes of water and hypochlorous acid demonstrate the salient features of electronic spectroscopy.The ground state photoelectron spectra of these compounds are used as teaching examples; we also examine the unique pedagogical advantages of the laboratory.