[Ifeffit] Hephaestus edge step calculation

[Guanghui Zhang]

Hello, Bruce.
Thanks very much for writing and keeping upgrading the amazing software. 
I was mainly doing homogeneous catalysis, so most of my samples were solution samples. I found that it was quite convienent to calculate the absoption length and edge step using the old version Hephaestus (ifeffit 1.2.11). Simply go to the Formulas tab, choose Molarity, type in the formula, molarity, and energy. The calculation results will show up after clicking the Compute button. For example, if I type in the Formula as Pt, molarity as 0.03 mol/L and Energy as 11564 eV (Pt L3 edge), the calculation results showed as follows:
  
element   number   barns/atom     cm^2/gm
 --------- ----------------------------------
    Pt       1.000   63044.107      194.641

This weighs 195.090 amu.

Absorbtion length = 0.878 cm at 11564.00 eV
for a 0.03 molar sample.

Unit edge step length at Pt L3 edge (11564.0 eV)
is 15108.1 microns


Remember that a molarity calculation only
considers the absorption of the solute.
The solvent also absorbs.

The Elam database and the total cross-sections
were used in the calculation.

However, in the new version Hephaestus (Demeter 0.9.22, trial version 4, Windows 8 64 bit). It does not work.
If I type the same informaiton, Pt, 0.03 mol/L, 11564 eV. The following results showed up.
element number barns/atom cm^2/gm
--------- ----------------------------------
Pt 1.000 63044.107 194.641
This weighs 195.090 amu.
Absorption length = 0.0 micron at 11564 eV for a 0.03
molar sample.
Unit edge step length at Pt L3 edge (11564.0 eV) is
0.0 microns
Remember that a molarity calculation only considers
the absorption of the solute. The solvent also
absorbs.
The Elam database and the full cross-sections were
used in the calculation.


If I do the calculation for the solid samples using "density" instead of "Molarity", the calculation worked fine.
I am wondering if there is any problem with my softwar and/or laptop, or there is a missing function in the new version Hephaestus.


Thanks
Guanghui




2015-06-18
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