[prev] [prev-tail] [tail] [up]

A.5 RFF Transitions

None of the RFF formulae needs an input parameter.

A.5.1 Including Contributions of LTE Levels (Unsöld)

2 s (n, T) = 3.694 .108ehnmin/kT --ZV ~ -- kk n3 T

nmin = min[n, nLT E]
nLTE is the ionization threshold energy of the lowest LTE level.

(cf.  Unsöld 1968)

A.5.2 Including Contributions of LTE Levels with Gaunt Factors

8 [ hnmin/kT ] --Z2--- skk(n, T ) = 3.694 .10 gff (n,T )(e - 1) 3 V~ -- n T

A.5.3 With Gaunt Factors, no LTE Contributions

8 --Z2--- skk(n, T) = 3.694 .10 gff (n,T ) 3 V~ -- n T

For the free-free Gaunt factors, the default is a calculation following Mihalas (1967, ApJ 149, 169). Since these values are calculated from a fit formula within 100 < c < 10000 Å and an extension to longer wavelengths, data (valid from submillimetre to hard X-ray wavelengths and for temperatures from 10 - 109 K) provided by Sutherland (1998, MNRAS 300, 321) can be chosen by input card (Sect. 5.4).

[prev] [prev-tail] [front] [up]