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

24 Sep 2015


      OK, at least we've come to convergence about what 'edge jump' means in this context.

Do you think the Elam value for (mu(+)-mu(-))_L3/(mu(+)-mu(-))_L2 is correct?
	mam

On 9/24/2015 10:36 AM, Matt Newville wrote:
...
Hi Matthew,
On Thu, Sep 24, 2015 at 11:47 AM, Matthew Marcus mailto:mamarcus@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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