The various relationships between spectroscopically measured quantities and the temperature and density of a collision-dominated plasma in local thermal equilibrium are discussed. An internally consistent system of corrections is derived for Saha equations, partition functions, and equations of state on one hand, and line intensities, line profiles, continuum intensities, and optical refractivities. The errors due to remaining uncertainties in these corrections are shown to be usually below 1%. They are therefore negligible compared to those stemming from uncertainties in atomic theory (except for hydrogen or hydrogenic ions) and an order of magnitude smaller than was suggested by discrepancies between previously used corrections to ionization energies of atoms or ions in dense plasmas.

• Received 25 May 1962

DOI:https://doi.org/10.1103/PhysRev.128.997