view Abstract Citations (2) References (11) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Radiative Relaxation of Hyperfine Populations Kwan, John Abstract The line radiation coupling two energy states produces a relaxation of hyperfine populations of each of the two states. This relaxation is effective if the hyperfine splittings are smaller than the thermal Doppler width of the line and if the stimulated radiative rates are high. Consideration of the relaxation of hyperfine populations among masing states can provide insight into the pump mechanisms. Among the four detected OH maser transitions at 18, 6.3, 5, and 2.2 cm, this relaxation process affects only the 2.2-cm transition if far-infrared lines alone are involved, but may affect all four maser transitions if near-infrared lines are also important. For H2CO, it is found that Dieter's previously proposed suggestion of nonequilibrium hyperfine populations is unlikely to be correct when radiative relaxation is included. Subject headings: hyperfine structure - masers radio lines Publication: The Astrophysical Journal Pub Date: July 1974 DOI: 10.1086/152946 Bibcode: 1974ApJ...191..101K full text sources ADS |