A Mechanism for a Maser Action of OH Molecules in Interstellar Space
Ian D. Johnston · The Astrophysical Journal · 1967
It is suggested that collisions between OH molecules and charged particles will discriminate between the different energy levels involved in the 18-cm wavelength transitions observed by radio astronomers, and hence could be responsible for a masering action on a vast scale. The basic atomic physics of the collision is analyzed, showing how this discrimination arises and what its consequences are in terms of observed microwave radiation. This simple collision process is then discussed in a kinetic theory context and results are derived which, though still highly idealized, have some point of contact with the real world. Finally, the general nature of the effect having been established, an attempt is made to show how it could be observed in interstellar space, and how it could be fitted to the OH observations in particular.