Hey, scientists--what causes fluorescence?

[glitterata]

I''ve been wondering.

 

[pricescope]

fluorescence: The emission of electromagnetic radiation, especially of visible light, stimulated in a substance by the absorption of incident radiation and persisting only as long as the stimulating radiation is continued.

See also http://en.wikipedia.org/wiki/Fluorescence

in short: Light (e.g. UV) causes some electrons to jump to a next energy level. When such supercharged electrons fall back to original energy level, they release photons back.

Diamonds should contain certain impurities to make such electrons available in the crystal lattice.

 

[DiamondExpert]

Fluoresecnce occurs when an atom''s electrons are excited, usually by short wavelength irradiation (UV, Xray, etc.), and then return to a lower energy level, releasing energy at a wavelength(s) in the visible range. It is visible only when added energy input is occuring.

 

[glitterata]

Thanks--that starts to answer my question.

I guess I should have asked, what causes fluorescence in a diamond?

Why do some have it and others don't? Why do some have more than others? Why do some have different colors of fluorescence?

 

[aphisiglovessae]

I''m not sure if it specifically applies to diamonds, but I read in an article from the Memphis Archaeological and Geological Society that fluorescence can be caused by certain disruptive factors (impurities or structure defects) in the crystal lattice. I also read somewhere that it is caused by trace amounts of boron.

This also came from the Thomas S. Warren Museum of Fluorescence:

A common result of beaming ultraviolet light on a material that absorbs rather than transmits it is that one or more of the electrons of an atom are "kicked" into a higher energy state, which here can be envisioned as moving to an orbit farther out from the nucleus. All such "excited" electronic states are unstable, and sooner or later the electron will lose its excess energy and fall back to its original orbit. This excess energy can be dissipated in several ways, the most common being simply to increase atomic vibrations in the material, but some materials also emit some of the energy as light. This is what we see as fluorescence.

 

[ecf8503]

Everything you ever wanted to know about fluoresence:

http://www.gia.edu/pdfs/W97_fluoresce.pdf


And the following is taken directly from Good Old Gold''s website:

How does it happen?

Diamond is crystallized carbon. This process happens about 75-125 miles below the surface of the earth and usually where volcanic or ancient volcanic sites exist where there was a lot of heat and pressure in the earth. If there are traces of the mineral boron present in the earth as this crystallization process is occurring the diamond will fluoresce. The various colors that diamonds can fluoresce can be blue, yellow, green, orange and white. Blue is the most common.

 

[valeria101]

What disturbance or micro-element causes this in diamonds... good Q that I do not know how to answer because I have not seen any bit of research on it.

Wonder if the folks making synthetics know !



Gliterata, on a recent thread you mention that your fave picking would be one colorless diamond with super strong fluorescence (''guess that is called ''overblue''). Wondering if you had the occasion to see a diamond with strong yellow color and yellow fluorescence. To me, such an example is the most beautiful incarnation of fluorescence among diamonds: it clearly serves color well both by adding to it and creating that tell tale slight haze that may not be so well liked on colorless diamonds expected to be crystal clear all the way. The result is simply glowing

 

[glitterata]

No, I''ve never (knowingly) seen a diamond with yellow fluorescence in person--that sounds very cool, I bet I''d love it.