Infrared Spectroscopy

Terry A. Ring

Chemical Engineering

University of Utah

Molecular Vibrations

• Mass on a spring

• Vibration Frequency

• ν=c/λ

• Wave number =1/ λ

Spectrometer

• Single Beam• Dual Beam

– with Reference

• Gas, Liquid & Solid• Sample Cells• Powder mixed with

KCl to make pellet• Reflection off surface

of Sample• Attenuated Total

Reflection

Sample

Sample

Spectrum

• Peak Identification

Spectrum

• Peak Identification– Valence Vibrations– Bending Vibrations

Peak Identification

Fourier Transform IR

• Mixing light from– Fixed mirror – Moving mirror

Raman Spectroscopy• Laser Light

Illumination

• Scattered Light Spectra Observed