IR spectroscopy

IR spectroscopyElectromagnetic RadiationRadiation is absorbed & emitted in photons. The defining characteristic of a photon is that the energy is quantized, it can not be split into smaller pieces.Each photons energy is defined by its frequency, () or wave length, () or wave number (wn)Ephoton = h = hc/ = hc(wn)Two constants appear in these formulas:h = 6.63 x x 10-34 J sc = speed of light = 3.00 x 108 ms-1 (3.0 x 1010cms-1)Wave number (wn) = 1/IR Radiation

IR absorbed by organic molecules 600 - 4000 cm- -1 1 Photon energy = hc(wn) = 1.2 - 8.0 x 10-20 J Molar photon energy = 7.4 -49 kJ/mol = 1.8 -12 kcal/mol IR photon energy Bending > Wagging/Twisting

Interpreting a spectrumFingerprint Region

Other helpful information

Sample IR spectrum

Another sample IR spectrum

Another sample IR spectrum

Another IR spectrum

Another IR spectrum