http://www.mso.anu.edu.au/~ralph/freefree.html

### Accurate Free-Free Gaunt Factors for Astrophysical Plasmas

Ralph S. Sutherland

#### Abstract:

New calculations of free-free transition matrix element integrals are performed using modern symbolic computing techniques to evaluate the hypergeometric functions with complex arguments. The results are presented in both graphical and tabular form including accurate extrapolation methods.

The results are accurate to the level of ($\sim 10^{-4}$) beyond which relativistic corrections would be needed, which are not included. The results are also computed over a very wide range of scaled ionic temperature ($\gamma^2$) and wavelength, extending earlier results to new regimes encountered in highly photoionised and non-equilibrium ionisation plasmas. These results will be useful in the spectral range from sub-millimeter to hard X-ray wavelengths and temperatures from 10K to 10$^9$ K.

You can get the file individually below or just http to my data area:

http://msowww.anu.edu.au/~ralph/data/freefree/

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