Does atomic fluorescence involve: 1. spontaneous emission (or only), 2. stimulated emission (or only) 3. change in magnetic quantum number $$\Delta m \neq 0$$ ? Thank you. Rarely can I find a definition on the internet. My guess is that atomic fluorescence involves spontaneous emission only. Fluorescence seems to be a term accompanying spontaneous emission only (but not involving stimulated emission), as in chemical compounds; while atomic Fluorescence seems to be a subset of Fluorescence. Does it always involve a change in magnetic quantum number?