# Definition question about atomic fluorescence

1. Jun 18, 2015

### td21

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?

Last edited: Jun 18, 2015
2. Jun 23, 2015

### Greg Bernhardt

Thanks for the post! This is an automated courtesy bump. Sorry you aren't generating responses at the moment. Do you have any further information, come to any new conclusions or is it possible to reword the post?

3. Jun 25, 2015

### td21

I especially hope to know if it always involves a change in magnetic quantum number. Can the term
atomic fluorescence include spontaneous emission with no change in magnetic quantum number? Thanks.

4. Jun 25, 2015

### Zarqon

I think a short answer to your question is: yes, spontaneous emission can occur without change in magnetic quantum number.

In fact, unless you specifically apply an external magnetic field, there IS no magnetic quantum number (I assume you mean the spin here?), and as such it cannot change. However, even in the case of an applied magnetic field, fuorescence can occur without changing the spin, since emission in a direction perpendicular to the magetic field quantization axis (and with a particular polarization) again cannot see the quantization axis and so cannot change the spin.

I tend to think of fluorescence as simply meaning spontaneous emission, regardless of the involved levels.