ISOELECTRONIC SYSTEMATIZATION
Line Strength Factor:
Sif mi mf
i | r/ao | f 2
Deduced from measured data:
Sif = [ if (Å) / 1265.38]3 gi Bif / i (ns)
Parametrized:
Z 2 Sif SH + b/(Z-C) ; SH = 3n2 (n2-1) gi / 4
1 and 2 free parameters:
Wolfe, PR 41, 443 (1932) (spin-other-orbit) King & VanVleck, PR 56, 464 (1939) (spin dep. radial wave fctn.)
sp
All applications to here are n = 0 resonance transitions:Alkali-metallike ns – np Alkaline-earthlike ns2 – nsnp
Are these data-based semiempirical methods also applicable to other types of transitions?
Yes, but there are no data!Lifetime data exist, but branching fraction data are essentially
non-existent for multiply charged ions
Exceptions:
Determination of branching fractions: Requires intensity calibration of detection apparatus as a function of wavelength
Standard lamps: continuum radiation fixed in laboratory beam light Doppler shifted
Line standards available in Visible, but not UV
Need in-beam ions with known intensity ratios