Full set of Notes with Fill-Ins - San Jose State University

Chem 155 Unit 12 232 of 316Conclusions and Questions:Infrared spectroscopy is important because:1. Virtually all molecules have a unique vibrationalspectroscopic signature in the infrared.2. Most molecules absorb strongly! So IR can bequite sensitive for both identification andquantitation.3. But IR radiation is harder to manage with amonochromator because sources are weak,detectors are less sensitive and high resolution isoften needed.4. So interferometry is done instead, which is bothinherently fast and high reseolution.Interferometry converts optical frequency directly intoa frequency on the detector:1. What frequency would a 3000 cm -1 sourceproduce in an interferometer operating with amirror velocity of 1 cm/s?2. If the mirror travel were 1 cm, what would be theresolution (Δλ EFF ) in cm -1 ?3. What will this value be in nm?4. What focal length would be needed with amonochromator with a 1000 nm grating spacingand slits at 0.4 mm?Page 232 of 316