The up’s and down’s of internal conversion

Internal conversion is a vital vibronic loss mechanism which competes with all other photophysical mechanisms, and available in the literature is a plethora of information on the subject. However, this data is often difficult to penetrate due to its complexity. As well, due to the sheer number of methods, it is often difficult to understand which method is better for certain systems. This comprehensive review on the state of the art explores the history of internal conversion and provides context to its evolution up to modern quantum chemistry. We highlight the most prevalent methods used to study atomic systems, where they rise, and where they fall. Crucially, we note each methods and the corresponding results in a simplified manner, and thread everything together to elucidate how everything is related. This tapestry illustrating the up’s and down’s of internal conversion will aid researchers in their study of new and innovative materials, and provides a vital comparison of methods not easily gained.