Electron number density (ne) calculated from the width of the
Hα lines was also used to assess validity of the standard matrices
for analysis of nails. The spectra used for the calculation were
acquired in the spectral window shown in Fig. 1. The full width of
the line at 656.2 nm was measured and an iterative calculation
was performed using the equation Δλ1/2¼2.50 109
α1/2ne
2/3
with α1/2 interpolated from tables by Griem [15]. The resulting
electron number densities for plasmas formed on the nails, filter
paper, and keratin pellet were 1.0 1016, 8.6 1015, and 7.7 1015
respectively. Because the width of the Zn line at 481.0 was also
greater than the spectrometer limited line width, this line could
also be used to estimate electron number density using Δλ1/2¼
2ωne/1016 according to Gojani [16]. In this case, using ω¼0.1 gives
electron densities of 1.2 1016, 1.3 1016, and 1.0 1016
cm3 for the nails, filter paper, and keratin pellet respectively. In
this case, it can only be concluded that the electron density of the
plasmas formed on the nails, filter papers, and keratin pellets were
all approximately 1016.