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Re: Halo blue- phosphors physics
> >Halo blue is a fluorescent powder made of calcium fluorophosphate activated
> >with
> >antimony.
> >It's exitation peak is at 220 nm, (so quite good for the production of a low
> >pressure mercury discharge lamp) and it's emission peak is at a wavelength
WOW, this is a subject I would like to hear more about! Not Halo Blue, per
> se, but the subject of phosphors. Seems we have an expert in our midst, in
> about compositions and how they work. F-Centers and all that. Are there any
> reference books on this subject for someone that can understand them and
> appreciate it?
> Jeff Golin
>
Dear Jeff,
physics of fluorescents is VERY complicated.
For a short overview, I could recommend any book on solid state physics
(p.ex. Kittel, Introduction to solid state physics). For advanced
literature, you should look on electronic structure of solid semiconductors.
But without knowldge of quantum mechanics, crystral structure and electronic
band structure is is wasted time.
Emitted color depends on very little changes in energy gaps of donators or
acceptors, and if phonons (quantized lattice movements) take part or not.
So even production of constant quality phosphors is a mysterium, you
need exact reproducible reagents and "sterile" conditions.
An easy standard green you might do yourself, but others are difficult.
A major advantage of the european dry ciating process is that colors are not
limited. You can mix the powders in nearly any relation to get a
shade of color. But there are other major disadvantages......
So don't mind neon and fluorescent powders are hand-waving physics,
it's nearly Ph.D. grade to understand all colors and how they work.
Marcus Thielen
Student of physics at Duisburg University
email:marcus@ttphysik.uni-duisburg.de
References: