Collisional depolarisation in electronically excited radicals

Recent work on collisional depolarisation in electronically excited radicals is reviewed, with a focus on the NO(A) and OH(A) radicals in collisions with rare gas atoms. The mechanism of depolarisation, and its competition with other collisional processes, is investigated using a combination of experimental and theoretical methods. The present state of the field is also put into context with other, related work in similar areas.