CDEX's patented technology (nbr 9,013,686) now under their new Technical Director for Spectroscopy Products, award winning John Coates, PhD
As disclosed above, system 100 identified and quantifies molecular and chemical compounds using Enhanced Photoemission Spectroscopy, or EPS. EPS utilizes at least three different kinds of light interactions with molecular structures. Preferably, the disclosed embodiments use three different light interactions, which correspond to modules 124-28. Additional modules may be added to system 100 for additional light interaction analysis implemented.
One type of interaction used in the disclosed processes is fluorescence. Fluorescence is the emission of light by a substance having electrons that absorb light at a different wavelength. It may be a form of luminescence. As used above, the emitted light is longer in wavelength than the incident light, and, therefore, also is lower in energy than the incident light. When the absorbed light is very intense, such as produced by a laser, it is possible for one electron to absorb two photons. This two photon absorption may lead to emission of radiation having a shorter wavelength than the incident radiation. Thus, errors may occur using only a fluorescence process to identify sample 110, since many molecule combinations produce a similar fluorescence spectrum.
Another type of light interaction is Raman interaction, disclosed above. If the incident light is scattered from molecules in the target of interest, such as sample 110, the majority of the incident photons are elastically scattered, also known as Rayleigh scattering. This scattering produces no shift in the wavelength compared to the incident photons. The minority of the incident photons, such as about 1 in 10.sup.7, are inelastically scattered by an excitation with the scattered photons having a wavelength different from, and usually higher than, the wavelength of the incident photons. If the target is a gas, Raman scattering may occur with a change in vibrational or rotational energy of the target molecules. Preferably, the disclosed embodiments utilize the vibrational Raman scattering effect.
In fluorescence, the interaction of incident light with molecular structures involves absorption of photons precisely matching the difference in energy levels of electrons in the target molecules. This interaction results in re-emission after a certain resonance lifetime. The results of fluorescence and Raman scattering are similar in that a photon with a frequency different from that of the incident photon is produced and the molecule is brought to a higher or lower energy level. The difference between the two methods is that the Raman effect may take place for any frequency of the incident light from light source 108. The Raman effect may not be considered a resonant effect. A fluorescent peak may be anchored to a specific frequency, but a Raman peak maintains a constant separation from the excitation frequency.
There may be two types of Raman scattering: Stokes and anti-Stokes. In Raman scattering, the effect detected by EPS system 100 relates to the absorption and subsequent emission that occurs through an intermediate quantum (vibrational state) of a material. No energy exchange may occur between the incident photons and the molecules. Thus, there is no Raman wavelength shift. Alternatively, energy exchanges may occur between the incident photons and the vibrational states of the molecules, which leads to Raman interaction. The energy differences are equal to the differences of the vibrational and rotational energy levels of the molecule.
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John Coates, Phd
Recipiant of the Coblentz Society's Williams-Wright Award
The Coblentz Society's Williams-Wright Award is presented annually to an industrial spectroscopist who has made significant contributions to vibrational spectroscopy while working in industry. The work may include infrared and/or Raman spectroscopy, instrumental development as well as theory, and applications of vibrational spectroscopy. Government labs are not considered industry in this definition. No restrictions are placed on the selection of the Awardee because of age, sex, or nationality, but the Awardee must still be working at the time the award is presented. The award consists of a frame certificate and an honorarium. In order to ensure that the award is based on an independent evaluation of the candidate’s achievements, the selection is made by a committee chosen by the Coblentz Society.
The Award is presented each year at the Pittsburgh Conference on Analytical Chemistry and Applied Spectroscopy. The Williams-Wright Award Symposium is held in honor of the awardee and immediately follows the presentation. In the picture to the right, John Coates was presented the 2013 Award with Shawn Mehrens (committee chair 2012-2013) and Jim Rydzak (Coblentz Society President 2013-2014).
The nomination should clearly state the significance of the contribution made by the nominee, e.g., the introduction of novel methods, techniques or theories; innovative work in the field of vibrational spectroscopy; significant improvement on existing methods, theory or techniques; or important impact on the field of vibrational spectroscopy arising from the volume of contributions in a specific area. The nomination packet should include a resume of the nominee's career including a publication list. Seconding letters to the nomination are useful, but not necessary. Files on nominees will be kept active for three years, after which the candidate must either be renominated with an updated file, or the file will be closed. Nominations should be sent to the Chair of the Williams-Wright Award Selection Committee. Nominations close May 1st for the 2016 award.
John Coates, Recipient of the Williams-Wright Award
