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Radiative trapping and population inversions of the SiO masers

Kwan, John and Scoville, Nick (1974) Radiative trapping and population inversions of the SiO masers. Astrophysical Journal, 194 . L97-L101. ISSN 0004-637X. doi:10.1086/181678.

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Radiative trapping in the v = 0 → 1 vibrational transitions decreases the rate of de-excitation of a v = 1 level as its rotational quantum number increases. This effect readily leads to population inversions of the v = 1 rotational transitions if population is transferred from v = 0 into v = 1 by collisions or by an indirect radiative route, as, for example, through absorptions from v = 0 into v = 2 and the subsequent spontaneous cascade from v = 2 to v = 1. Numerical calculations which model the SiO masers discovered toward stars give photon emission rates in the J = 1 → 0, J = 2 → 1, and J = 3 → 2 transitions which are comparable and substantial, 3 x 10^(43) s^(-1).

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Scoville, Nick0000-0002-0438-3323
Additional Information:© 1974. The American Astronomical Society. Received 1974 August 14; revised 1974 September 18. This research is sponsored by the National Science Foundation grant GP-40768X (J.K.) and GP-30400-X5 (N.S.) and by the Office of Naval Research under contract N0014-67-A-0094-0019 (N.S.). We thank Drs. P. Goldreich and P. Solomon for very helpful discussions. We also thank Dr. Roger Thompson for informing us that the CO V = 0 → 1 lines have Einstein B coefficients of absorption that are comparable to those of SiO V = 0 → 1 lines.
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Office of Naval Research (ONR)N0014-67-A-0094-0019
Subject Keywords:masers — radiative transfer
Record Number:CaltechAUTHORS:20190403-153008551
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Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:94431
Deposited By: George Porter
Deposited On:11 Apr 2019 20:07
Last Modified:16 Nov 2021 17:05

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