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Laser Spectroscopy: TDLAS instrumentation and NIR analysis of some organic materials
| Content Provider | CUSAT-Thesis |
|---|---|
| Advisor | Dr.Rajappan Nair,K P |
| Researcher | Shibu, Eappen M |
| Abstract | Near-infrared spectroscopy can be a workhorse technique for materialsanalysis in industries such as agriculture, pharmaceuticals, chemicals and polymers. Anear-infrared spectrum represents combination bands and overtone bands that areharmonics of absorption frequencies in the mid-infrared. Near-infrared absorptionincludes a combination-band region immediately adjacent to the mid-infrared and threeovertone regions. All four near-infrared regions contain "echoes" of the fundamental mid-infraredabsorptions. For example, vibrations in the mid-infrared due to the C-H stretches willproduce four distinct bands in each of the overtone and combination regions. As thebands become more removed from the fundamental frequencies they become morewidely separated from their neighbors, more broadened and are dramatically reduced inintensity. Because near-infrared bands are much less intense, more of the sample can beused to produce a spectra and with near-infrared, sample preparation activities aregreatly reduced or eliminated so more of the sample can be utilized. In addition, longpath lengths and the ability to sample through glass in the near-infrared allows samplesto be measured in common media such as culture tubes, cuvettes and reaction bottles.This is unlike mid-infrared where very small amounts of a sample produce a strongspectrum; thus sample preparation techniques must be employed to limit the amount ofthe sample that interacts with the beam. In the present work we describe the successful the fabrication and calibration of a linear high resolution linear spectrometer using tunable diode laser and a 36 m path length cell and meuurement of a highly resolved structure of OH group in methanol in the transition region A v =3. We then analyse the NIR spectrum of certainaromatic molecules and study the substituent effects using local mode theory |
| File Format | |
| Language | English |
| Publisher Institution | Cochin University of Science and Technology |
| Access Restriction | Open |
| Subject Keyword | Tunable diode laser absorption spectroscopy, Semicondutor diode, Spectroscopy, |
| Alternative Title | TDLAS instrumentation and NIR analysis of some organic materials |
| Content Type | Text |
| Educational Degree | Doctor of Philosophy (Ph.D.) |
| Resource Type | Thesis |
