Abstract
A new excitation mechanism for interstellar Class II methanol masers—maser without population inversion is argued. The 107 GHz masers is taken as an example to demonstrate that our new mechanism is associated with astronomical conditions.
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Liu, H., Forster, J.R. & Liu, Y. A feasible excitation mechanism for interstellar Class II methanol masers. Opt Quant Electron 39, 1311–1318 (2007). https://doi.org/10.1007/s11082-008-9210-0
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DOI: https://doi.org/10.1007/s11082-008-9210-0