[Ifeffit] Problem with Hephaestus at Ca L-edges (Matthew Marcus)

[Matt Newville]

Hi Matthew,

On Thu, Sep 24, 2015 at 11:47 AM, Matthew Marcus <mamarcus at lbl.gov> wrote:

> What I was after was L3/L2, so I don't care about L1.  The attached plot
> doesn't show the jumps for both L2 and L3.
>
> When you say that the edge jumps are 5.8,1.4 and 1.1, are you referring to
> mu(+)/mu(-)?  I was looking for (mu(+)-mu(-))_L3/(mu(+)-mu(-))_L2.
>

Sorry, finer data (0.20 eV steps) across the L3 and L2 edge attached.
Chantler's data clearly do not give good values for the Ca L2 edge.

The edge jumps I reported are those reported in the Elam tables, which are
described there (see
https://github.com/XraySpectroscopy/XrayDB/blob/master/src/elam.dat#L79)
as

   mu(+) DIVIDED BY mu(-).

That clarifies those values for me, anyway!
If I do (mu(+)-mu(-))_L3/(mu(+)-mu(-))_L2 with the Elam values for mu, I
get 2.1.

Revised script:

#############################
info_head = 'Ca edge Energy(eV)  Fyield   EdgeJump'

info_l3 = ' L3       %.1f    %.5f    %.2f' % xray_edge('Ca', 'L3')
info_l2 = ' L2       %.1f    %.5f    %.2f' % xray_edge('Ca', 'L2')
info_l1 = ' L1       %.1f    %.5f    %.2f' % xray_edge('Ca', 'L1')

l3_en = xray_edge('Ca', 'L3')[0]
l2_en = xray_edge('Ca', 'L2')[0]
l3_jump = mu_elam('Ca', l3_en+1) - mu_elam('Ca', l3_en-1)
l2_jump = mu_elam('Ca', l2_en+1) - mu_elam('Ca', l2_en-1)

info_jump = 'Jumps: L3=%10.1f, L2=%10.1f, L3/L2=%10.3f'
info_jump = info_jump % (l3_jump, l2_jump, l3_jump/l2_jump)

energies = linspace(340, 360, 101)
muca_chantler = mu_chantler('Ca', energies)
muca_elam = mu_elam('Ca', energies)

newplot(energies, muca_chantler, ymax = 50000, label='Chantler',
        xlabel=r'$E\rm\, (eV)$', ylabel=r'$\mu\rm\, (cm^2/gr)$',
        show_legend=True, title='Ca L3, L2 edges')
plot(energies, muca_elam, label='Elam')


write_ascii('CaMu_fine.dat', energies, muca_elam, muca_chantler,
             info_head, info_l3, info_l2, info_l1, info_jump,
             label='Energy  MuCa_Elam  MuCa_Chantler')
#############################



> What about that seeming inconsistency between the values H. gives for the
> thickness needed for unit edge step and the cm^2/gm values reported? That
> seems to be a bug indpependent of
> the tables used.
>

Not sure.

--Matt
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