Chemistry: Spectroscopy: Reading Between the Lines

Spectroscopy: Reading Between the Lines

Though Bohr spent his time thinking about the emission lines in hydrogen's spectrum, hydrogen isn't the only element that produces a line spectrum. In fact, all elements produce a unique line spectrum, because all elements have unique orbital energies. You can use these emission spectra to identify the elements in a sample of an unknown compound. The method of identifying substances by their spectra is called spectroscopy.

Molecular Meanings

Spectroscopy is a method of identifying unknown substances from their spectra. Because all materials have unique spectra, you can think of these spectra as being "molecular fingerprints."

Although there are many different types of spectroscopy, they all work under the same principle. Some important varieties of spectroscopy include infrared (IR) spectroscopy, UV-vis spectroscopy (which uses light in the ultraviolet and visible range of the spectrum), and nuclear magnetic resonance spectroscopy (a.k.a. NMR spectroscopy, which uses pulsed radio waves).

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Excerpted from The Complete Idiot's Guide to Chemistry © 2003 by Ian Guch. All rights reserved including the right of reproduction in whole or in part in any form. Used by arrangement with Alpha Books, a member of Penguin Group (USA) Inc.

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