Anion Photoelectron Spectroscopy is a valuable weapon in the arsenal of spectroscopic endeavours. In essence, one targets a stable anion to access the neutral potential energy surfaces via detachment and analysis of electrons garners electronic and vibrational information. Targeting loosely bound anion-molecule complexes, X- ··· M can provide a snapshot of the reactive neutral radical potential energy surfaces. The species are readily selected, via mass spectrometry, ensuring that the spectrum is uncomplicated.
This contribution will highlight recent anion photoelectron spectroscopy experiments coupled with high level ab initio calculations. As a pertinent example, the entrance and exit channels for the Br- + CH3I → CH3Br of the SN2 reaction were identified from the anion photoelectron spectrum which revealed evidence of the reaction occurring in the ion source of the apparatus [1].
References:
1. T. Robinson, T.R. Corkish, C.T. Haakansson, P.D. Watson, A.J. McKinley, and D. A. Wild. ChemPhysChem, e202200278, doi.org/10.1002/cphc.202200278