Radiative pumping of 1612 MHz OH masers: OH/IR sources with IRAS LRS spectra and 34.6 micrometer absorption feature

R. Szczerba, J. H. He, P. S. Chen

The population inversion which leads to the 1612 MHz OH maser emission has long been thought to be radiatively pumped. Since OH rotational lines involved in this pumping scheme lie…