Stark Coefficients for the Balmer Series Lines

    The Stark-broadened absorption coefficient for the Balmer Series Lines is given approximately by the expression (this expression works well for the wings of all of the Balmer lines except Hα , for which self-broadening is a problem; it works less well for the cores of the lines which are affected by Doppler broadening):

where Δλ is in Å and all other quantities are in cgs units.  The constants Cn (and also the f-values) for the Balmer Series lines are given in the following table:

Line nupper term f Cn   Line nupper term f Cn
Hα 3 0.6408 3.15 ´ 10-16   Hι 11 0.191 ´ 10-16
Hß 4 0.1193 0.887 ´ 10-16   Hκ 12 0.185 ´ 10-16
Hγ 5 0.0446 0.446 ´ 10-16   Hλ 13 0.180 ´ 10-16
Hδ 6 0.02209 0.332 ´ 10-16   Hμ 14 0.177 ´ 10-16
Hε 7 0.261 ´ 10-16   Hν 15 0.173 ´ 10-16
Hζ 8 0.231 ´ 10-16   Hξ 16 0.171 ´ 10-16
Hη 9 0.212 ´ 10-16   Hο 17 0.170 ´ 10-16
Hθ 10 0.200 ´ 10-16   Hπ 18 0.168 ´ 10-16