Experimental infrared spectroscopy

The infrared spectrum was discovered by Herschel in 1800. He found that a thermometer was heated by invisible radiations when he placed it beyond the red end of a solar spectrum formed by a glass prism. From this primitive discrimination between the visible and invisible, experimental physicists have refined their procedures until now the $\text{15,000\hspace{0.17em}}{\mathrm{cm}}^{\text{−1}}$ compass of that invisible spectrum is resolved into some 30,000 separable subdivisions of $\text{1/2\hspace{0.17em}}{\mathrm{cm}}^{\text{−1}}$ width, with prospects of resolving it into 200,000 subdivisions in the near future.

This article is only available in PDF format