GammaX-rayUVVisIRMicroRadio Short wavelength High energy High frequency Long wavelength Low energy Low frequency Solvent effects: Neat: has fine structure Solvent: has smoothing effects, loses din structure The more polar the solvent, the more interactions the solvent has with the spectrum

 A = єbc ◦ A is absorbance ◦ Є is molar absorptivity ◦ b is path length ◦ C is concentration Used for UV-Vis calculations UV-Vis Block Diagram Tungsten filament lamp MonochromatorCell Holder Photomultiplier Tube

Luminescence Block Diagram L.A.S.E.R. = Light Amplification through Stimulated Emission of Radiation Steps: 1. Pumping 2. Spontaneous emission 3. Stimulated emission 4. Absorption SourceMonochromatorCell Holder Photomultiplier Tube

Monochromator- an optical device that transmits a narrow band of wavelength of light or radiation chosen from a wide range of wavelengths Types: Prism-get 3D lightGrating- get 2D light can change wavelength selected by moving the reflection grating

Transducer-amplifies electrical signals ◦ Photoconductivity ◦ Thermal ◦ Photon ◦ Multichannel photon Interferometer Moving mirror is important because it reflects the source wavelength and can constructively y or destructively interfere with the source, even completely negate it Better than monochromator because has infinite ways of transmitting narrow wavelengths Can collect a lot of data in a short amount of time One back and forth is one IR scan