Spectroscopy beyond molecular constants

Abstract The spectra of diatomic molecules containing an atom with a partially filled d or f shell are exceedingly complex. Nonetheless, simple bonding arguments and a simple, predictive zero-order electronic structure model can be used to organize and understand the unavoidably dense and confusing manifold of molecular states. The correspondence between molecular constants and a global periodicity-based structural model is only possible when large quantities of spectral information have been acquired and deciphered. This paper discusses how a variety of new and powerful, single and multiple resonance spectroscopies can be used to efficiently and rapidly generate the large amounts of high quality spectral information required to reveal what appears to be an elegant underlying electronic simplicity.