Millimeter and Submillimeter Wave Spectroscopy and Astrophysical Applications
Published Online: 15 SEP 2011
Copyright © 2011 John Wiley & Sons, Ltd. All rights reserved.
Handbook of High-resolution Spectroscopy
How to Cite
Ziurys, L. M. 2011. Millimeter and Submillimeter Wave Spectroscopy and Astrophysical Applications. Handbook of High-resolution Spectroscopy. .
- Published Online: 15 SEP 2011
Millimeter and submillimeter spectroscopy has played a crucial role in the discovery and study of interstellar molecules by radio astronomy, as well as in the characterization of the rotational energy levels for numerous chemical compounds. A broad range of spectrometer designs have been developed for this basic direct absorption technique. Certain systems employ “free space” cells and Gaussian beam optics, while others incorporate mirrors in multipass configurations. Fast scanning methods have additionally been implemented. Synthetic techniques are also important in the astrophysical application of millimeter/submillimeter spectroscopy, as many potential interstellar species are free radicals and molecular ions. Many instruments employ glow discharges, ovens, and other exotic gas-phase methods for the creation of transient molecules. Radical spectra usually exhibit a range of fine structure and hyperfine interactions which can complicate their analysis. Another challenge for millimeter/submillimeter spectroscopy is the study of simple organic molecules with functional groups that undergo hindered rotation. Millimeter and submillimeter spectroscopic measurements continue to provide the necessary rotational “rest frequencies” for molecule identification in space. Recent work has led to the interstellar discoveries of long-chain carbon anions C4H− and C6H−, more complex organic molecules including CH3CONH2, and unusual refractory species such as CCP and AlO.
- millimeter methods;
- submillimeter methods;
- rotational spectroscopy;
- open-shell species;
- interstellar molecules;
- radio astronomy