A table of departure coefficients from thermodynamic equilibrium /b[SUB]N[/SUB] factors/ for hydrogenic ions

Abstract

The formation of hydrogenic radio recombination lines is examined, and frequencies, emissivities, and absorption coefficients for line radiation are analyzed. Departure coefficients from thermodynamic equilibrium (b<SUB>n</SUB> factors) are computed for a range of physical conditions in H II and H I regions for the case where radiation due to transitions to the ground state is reabsorbed but all other radiation escapes freely. The transfer equation is solved analytically for a cloud of uniform composition illuminated by a background H II region of given electron temperature and emission measure.