ATOM AND VALENCE ELECTRON SIGNALS – X-RAYS – GAMMA-RAYS
Radiation
γ-rays
x-rays
Vacuum
UV
UV
Visible
IR
Microwaves
E range
0.1 to 0.0001 nm
50 to 0.1 nm
What can it do
Can promote or remove inner (core) electrons
Can promote or remove inner (core) electrons
Can break molecular bonds. Results in the removal
10-190 nm
or promotion of electrons to excited states
Can break molecular bonds. Results in the removal
190-300 nm
or promotion of electrons to excited states
Results in the removal or promotion of electrons to
350 to 800 nm
excited states
0.8-300 μm
Increases the amplitude of vibrations
~1-4 mm
Increases the rate of molecular rotation
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WHAT ATOM CAN SAY TO US?
Infrared
(outer electrons and/or
valence electrons)
Infrared Spectroscopy is the
analysis of infrared light
interacting with a molecule.
This can be analyzed in three
ways by measuring absorption,
emission and reflection.
The main use of this technique
is in organic and inorganic
chemistry. It is used by
chemists to determine
functional groups in molecules.
IR Spectroscopy measures the
vibrations of atoms, and based
on this it is possible to
determine the functional
groups. Generally, stronger
bonds and light atoms will
vibrate at a high stretching
frequency (wave number).
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UV-Vis-NIR
(outer electrons and/or
valence electrons)
UV/Vis spectroscopy is
routinely used in analytical
chemistry for the quantitative
determination of different
analytes, such as transition
metal ions, highly conjugated
organic compounds, and
biological macromolecules.
Refers to absorption
spectroscopy or reflectance
spectroscopy in the ultravioletvisible spectral region. This
means it uses light in the
visible and adjacent (near-UV
and near-infrared [NIR])
ranges. The absorption or
reflectance in the visible range
directly affects the perceived
color of the chemicals
involved. In this region of the
electromagnetic spectrum,
molecules undergo electronic
transitions. This technique is
complementary to fluorescence
spectroscopy, in that
fluorescence deals with
transitions from the excited
state to the ground state, while
absorption measures transitions
from the ground state to the
excited state.
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X rays
(inner electrons)
The most abundant is X-ray
emission spectroscopy. It is
routinely used for qualitative
and quantitative analysis of
inorganic materials. There are
two types of X-ray emission
spectroscopy:
 Energy-dispersive X-ray
spectroscopy (EDS), and
 Wavelength dispersive Xray spectroscopy (WDS).
When an electron from the
inner shell of an atom is excited
by the energy of a photon, it
moves to a higher energy level,
which is shown as an outer
shell; the difference in energy
is emitted as a photon which
has a wavelength that is
characteristic for the element
(there could be several of
characteristic wavelengths per
element). Analysis of the X-ray
emission spectrum produces
qualitative results about
elemental composition of the
specimen. Comparison of
spectrum of the specimen with
spectra of standards of known
composition produces
quantitative results (after some
mathematical corrections for
absorption, fluorescence and
atomic number).
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Gamma rays
(from atom nucleus)
Gamma spectroscopy is
the science of identification
and/or quantification of
radionuclides by analysis of
the gamma-ray energy
spectrum produced in a
gamma-ray spectrometer.
It is a widely used technique.
Most radioactive sources
produce gamma rays, which are
of various energies and
intensities. When these
emissions are detected and
analyzed with a spectroscopy
system, a gamma-ray energy
spectrum can be produced. A
detailed analysis of this
spectrum is typically used to
determine the identity and
quantity of gamma emitters
present in a gamma source, and
is a vital tool in radiometric
assay. The gamma spectrum is
characteristic of the gammaemitting nuclides contained in
the source, just as in optical
spectroscopy, the optical
spectrum is characteristic of the
material contained in a sample.
Gamma-ray spectroscopy is
the quantitative study of the
energy spectra of gamma-ray
sources, in such as the nuclear
industry, geochemical
investigation, and astrophysics.
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Spectroscopy
Infrared
UV-Vis-NIR
X-ray and
Photoelectron
Nucleon
Radio wave
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FT-IR
Raman
Rotational
Vibrational
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Ultraviolet-visible
Fluorescence
Vibronic
Near-infrared
Laser-induced
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Photoelectron
Atomic
Emission
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Gamma
Mössbauer
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NMR
Terahertz
ESR/EPR
Ferromagnetic resonance
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