Fermi-Dirac Averages of the Free-Free Hydrogenic Gaunt Factor
A study of the effects of very high electron densities on the absorption of radiation by free-free electron transitions. The absorption coeffecient is expresssed in terms of a dimensionless quantity known as the Gaunt factor. The nonclassical effect of exclusion is obtained by averaging the energy dependent hydrogenic Gaunt factors of Latter and Karzas against the Fermi-Dirac electron distribution. Tables of the Fermi-Dirac averages of the hydrogenic Gaunt factor are presented over an appropriate range of thermodynamic states and photon energies. It is demonstrated that whenever the densities are high enough to require the use of the Fermi-Dirac averages, the effect of electron screening also becomes important. It is shown how the tables of Fermi-Dirac Gaunt factor integrals may be altered to determine the effect of electron screening.