Gaunt factors for free-free transitions in the fields of positive ions of carbon,nitrogen, and oxygen,calculated in the scaled thomas-fermi approximation

For air plasmas of higher temperature (1.5–2.5 eV) at normal pressure an essential part of the continuous opacity in the visible and near ultraviolet region is generated by free-free transitions of electrons in the fields of positive ions of carbon, nitrogen, and oxygen. Since the hydrogenic approximation leads to values for the thermally averaged Gaunt factor which are significantly too low, calculations are performed by means of the Scaled Thomas-Fermi approximation and compared with other theoretical results.