The photodissociation of an isolated molecule from a well-defined initial quantum state provides a lens through which one can investigate how and why chemical reactions occur, and provides numerous opportunities for fruitful, synergistic collaborations with high level ab initio quantum chemists. The chosen molecules in this review, their photofragments, and the subsequent chemical reaction networks to which they can contribute, are all crucial in planetary atmospheres and in interstellar and circumstellar environments.
