A Caltech Library Service

Radiative Trapping and Hyperfine Structure: HCN

Kwan, John and Scoville, Nick (1975) Radiative Trapping and Hyperfine Structure: HCN. Astrophysical Journal, 195 . L85-L88. ISSN 0004-637X.

[img] PDF - Published Version
See Usage Policy.


Use this Persistent URL to link to this item:


The anomalous weakness of the F = 1 → 1 hyperfine component in the J = 1 → 0 emission of interstellar HCN can be caused by radiative trapping in the J = 2 → 1 lines. The anomaly is readily produced if the J = 1 levels are populated largely by collisional excitation from J = 0 to J = 2 followed by radiative decay to J = 1 with the J = 2 → 1 lines optically thick. Regions where the anomaly is found probably have H_2 densities less than 10s^5 cm^(-3) and optical depths in the J =1 → 0 lines greater than 50.

Item Type:Article
Related URLs:
URLURL TypeDescription
Scoville, Nick0000-0002-0438-3323
Additional Information:© 1975. The American Astronomical Society. Received 1974 September 12; revised 1974 October 29. This research is sponsored by the National Science Foundation grants GP-40768X (JK) and GP-30400-X5 (NS) and by the Office of Naval Research under contract N0014-67-A-0094-0019 (NS).
Funding AgencyGrant Number
Office of Naval Research (ONR)N0014-67-A-0094-0019
Subject Keywords:hyperfine structure — molecules, interstellar
Record Number:CaltechAUTHORS:20190403-153008650
Persistent URL:
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:94432
Deposited By: George Porter
Deposited On:11 Apr 2019 20:03
Last Modified:03 Oct 2019 21:03

Repository Staff Only: item control page