Role of the gaunt factor in the derivation of dielectronic recombination coefficient

A new formula for the coefficient of dielectronic recombination has been derived by substituting excitation cross-section extrapolated below threshold for capture cross-section in Equation (7) of Burgess (1964). In this case the excitation cross-section modified by Mewe (1972b) through a fitted gaunt factor has been used. The dielectronic recombination coefficients calculated by the new formula are found to be about an order of magnitude smaller than those obtained by Burgess simplified formula. The results for coronal ions of silicon and iron are presented here as our sample calculations. A comparative study of the dielectronic recombination with radiative recombination is also made.