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Infrared Spectroscopy. Chapters 16-17 Chapter 7- I. IR Selection Rules. Change in dipole moment during vibration. Water Vibrations. http://www.lsbu.ac.uk/water/vibrat.html. Carbon Dioxide Vibrations. http://chemmac1.usc.edu/Bruno/java/Vibrate.html. FT-IR.
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Infrared Spectroscopy Chapters 16-17 Chapter 7-I
IR Selection Rules • Change in dipole moment during vibration
Water Vibrations http://www.lsbu.ac.uk/water/vibrat.html Carbon Dioxide Vibrations http://chemmac1.usc.edu/Bruno/java/Vibrate.html
Infrared Sources • Glowbar • Nernst glower • Patented sources
Detectors • DLaTGS (pyroelectric) • MCT (semiconductor/quantum well) • Thermodetectors (not used for FT-IR, response time is too slow) • Thermocouple • Bolometer • Thermister
FT Method Advantages • Fellget Advantage (Multiplex Adv) • Collect all at once • Faster, don’t need to scan axis • Jaquinot Advantage (Throughput Adv) • No slits or optical elements to limit (attenuate) radiation • Connes Advantage • Internally calibrated w/ HeNe laser • Wavenumber calibration is: • More accurate • Better stability