I might say that color vs particles size is difficult to qualify. It is a fact that a spherical particles of silver will absorb a fairly narrow band of light, whereas the wavelength of the light increases as the particle size increases. Also it can be said that when the particle size is sufficiently small (ions for example), the absorption is outside the visible spectrum, in this case in the uv spectrum, so it will appear clear and colorless to the unaided eye.
However when we get to the real world things get a mite more complicated. What about a rod shaped particle? If I read the research correctly, a rod shaped particle will tend to have two absorption peaks, one corresponding to the diameter of the rod and the other to the length of the rod. Now if we have something that is closer to a snowflake, it can have absorption peaks all over the place, since there are many many dimensions that can resonate at different wavelengths. It is quite possible that a large snowflake which is built up from lots of small particles, yet each bound by very thin whiskers, could have it's primary absorption in the uv region, although the full compliment of of this bundle of particles could measure rather large. However in that case there should be a very strong TE. There is another effect one has to be aware of as well. That is that when the particles get large enough, they will not absorb in the visible spectrum either, but rather in the infrared. Thus very large and very small particles can both be clear, although the very large ones should have a high TE and if there is any concentration at all, would be turbid. Marshall "Robert L. Berger" wrote: > Ken; > > I have the data sheets and theTEM for CS made with 380 v dc. the CS is > colorless just like water but the TEM from Texas > show particle size ranging form 18 nm to about 86 nm. Somuch for particle > size and color. If you want a pix of it I will send to individuals as it > exceeds Mike's bandwidth. > > "Ole Bob" > > -- > The silver-list is a moderated forum for discussion of colloidal silver. > > To join or quit silver-list or silver-digest send an e-mail message to: > [email protected] -or- [email protected] > with the word subscribe or unsubscribe in the SUBJECT line. > > To post, address your message to: [email protected] > Silver-list archive: http://escribe.com/health/thesilverlist/index.html > List maintainer: Mike Devour <[email protected]>
