Transmission Analysis of Gases and Vapors

A gas is any material whose boiling point is at or below ambient temperature, resulting in all the molecules of the material being in the gas phase at that temperature. Well-known examples of gases include oxygen, nitrogen, and carbon dioxide. A vapor is composed of molecules of a material in the gas phase that exists in equilibrium 

FIGURE 4.29 Two holders for FTIR gas cells. (Photo courtesy PIKE Technologies.) 

FIGURE 4.30 A gas-handling manifold that can be used to fiU and evacnate FTIR gas cells. 

The background spectrum can be run on an evacuated cell or a cell filled with an infrared transparent gas such as nidogen. 

FIGURE 4.31 A diagram of a White cell, whose design gives gas cells of high pathlength and small volume. 

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