BASICS:
For the purpose of determining what may be in an unknown sample, science has
devised various techniques. These techniques are divided into two
categories: analysis of the electron cloud; and analysis of the atom's nucleus.
ANALYSIS OF ELEMENTS BY ELECTRONS
Analysis of an element by its electron cloud was first discovered in wet
chemistry 100's of years ago. This is when chemists took different
chemicals and found that by adding different solutions together, they were
able to see color changes. This is even represented in the Old Testament
Book of Daniel by the Purple of Cassius. It was determined that if you had
an acid solution of gold and place stannous chloride (tin chloride) in it,
the solution would turn purple. Hence, a determination of gold by the
change of color.
In modern times, science has found that if you excited an atom to a certain
point it would emit various rays of light. This science was given the name
emission spectroscopy. Today, you will find spectroscopy widely used in
analytical techniques. Also, you will find that there are numerous ways
that science has determined to excite electrons whereas they can emit a
spectrum for detection by various means.
Examples of such excitation forces include --Carbon arcing, Acetylene, Argon
Plasma, Laser, and Microwaves.
After the original discovery of spectroscopy, it was found that if you
bombarded an atom with energetic particles (typically x-rays) you could
cause the intermost electrons to change orbits. This analysis is favored by
some for it does not require extensive sample preparation. The flip side is
-- the machinery is quite expensive. You will find this type of technology
employed in Scanning Electron Microscopes, X-ray Fluorescence, and similar
instruments.
ANALYSIS OF ATOMS BY THEIR NUCLEUS
Science advanced by determining that there were distinct differences in the
nucleus of an atom which would identify it from another.
The most common process to accomplish this is mass spectroscopy. This is
where a sample is volatized and sent through electrostatic deflecting
plates. By measuring the speed as to where a particle hits the detector,
determines its mass. Of course an example of this would be the Inductively
Coupled Plasma Mass Spectrometer (ICP/MS).
A second procedure, which is not as efficient as the above is Nuclear
Magnetic Resonance. In this process, atoms are placed in a magnetic field
which has an superimposed radio frequency. When the proper frequency is
achieved, a resonance is detectable and the atom is identified. The problem
with this type of analysis is only certain isotopes of select atoms have
magnet resonance characteristics. Hence, this type of analytical tool has
certain limitations.
The third process of determination by nucleus characteristics is Neutron
Activation. To start, there are only a few neutron activation centers in
the world. The reason is the cost and the disposal of radioactive material
after the test. In this procedure a sample is bombarded with neutrons.
These neutrons are absorbed by the atom's nucleus at a rate equal to the
thermal nuclear cross section for the particular characteristic of the atom.
(The reality is -- for the isotope of the atom) The thermal nuclear cross
section is a number derived from empirical data, not mathematical. Since
this particular topic has been discussed on the forum, I will add some
specifics.
Gold as found in nature has only one isotope, this being 79Au197. In
neutron activation, gold is bombarded with neutrons causing it to be
converted to 79Au198 (the equivalent of absorbing one neutron). 79Au198 has
unique characteristics, the most important being that it is radioactive with
a half life of 2.694 days. In its radioactive state it radiates beta
particles of a known energy. By analysis of the decay term (half-life) and
the energies of decay, the operator is able to identify the presence of gold
in the original sample. As this radioactive gold decays, it converts to
80Hg198, or stable mercury.
There is nothing within this evasive procedure that will detect the presence
of super conducting atoms, monoatomics, or the like. This procedure does
not have an interaction with the electron cloud, nor the asymmetry of the
nucleus. All atoms present will become radioactive at a rate proportional
to their thermal nuclear cross section quotient.
I HOPE THIS HELPS!!!!!!
_______________________________
Joe Champion discpub@netzone.com
http://www.netzone.com/~discpub