27;t think it's necessarily impossible, I just personally put it in the
not-right-now basket.
> On Sep 14, 2023, at 07:42, Mike Massey wrote:
>
>
> In my experience the main difficulties with EXAFS on P (phosphate) come from
> two factors (not signal to noise, it's no
In my experience the main difficulties with EXAFS on P (phosphate) come from
two factors (not signal to noise, it's not hard to get a nice smooth line, but):
1) You've got 4 O atoms, guaranteed, so any other signal will be small and on
top of that very strong signal generated from the first-neig
A question because I'm not really super clear on how harmonics work: (I'll get to the question in a moment...) I note that I0 starts to go non-linear around 12200-12400 eV and stays that way. So an increase (proportional?) in the amount of signal in It might be happening at around the same point.Co
Hi Patricia,
When you say "worse than the initial one," what do you mean?
If it's a "worse" match than nonsensical fit results, but makes some physical
and chemical sense, I'd personally argue it's a much better fit ;)
What you are doing seems reasonable to me, but I would further recommend
k
Hi All,
And now for something not-phosphorus...
Does anyone happen to have a wyartite U L3-edge XAS spectrum laying around?
If you do, and happened to be willing to talk with me about it, I would be
most grateful.
Kind Regards,
Mike
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Yes I was wondering about this as well. Technically P(III) exists, and maybe
one could find it in an AMBR? But I don't think anyone has a clue about what
the K-edge XANES spectrum looks like.
Has anyone ever collected a phosphite spectrum? That would be pretty cool. I
would totally do it but I'
t
> or, via email, send a message with subject or body 'help' to
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I recommend diluting this sample by a lot (20x maybe, or more) and collecting
another spectrum. I've had instances of strange features in P spectra that
ended up being weird self-absorption type artifacts.
I will dig through the spectra I have from similar samples, this one reminds me
of a spec
It sounds to me like you are understanding things well. The short, short
version is that the purpose of the rbkg parameter is to filter out the
low-frequency oscillations (arising from any of numerous sources) in the
spectrum, that correspond to interatomic distances that make no physical sense.
harp peaks in CO2 gas at 292.74 and 294.96eV.
>mam
>
>> On 5/7/2020 3:09 PM, Mike Massey wrote:
>> Hi Matt,
>> Indeed, in my experience (which is limited to one beamline at one
>> synchrotron facility for P XAS), once it is calibrated, the energy selection
>>
t
again.
Best,
Mike
> On May 8, 2020, at 8:51 AM, Matt Newville wrote:
>
>
> Hi Mike,
>
>
>> On Tue, May 5, 2020 at 10:56 PM Mike Massey wrote:
>> On a tangentially related topic, I find that phosphorus K-edge XAS energy
>> calibration conventio
On a tangentially related topic, I find that phosphorus K-edge XAS energy
calibration conventions are still in a bit of a "Wild West" state, with a wide
variety of materials and values in use for energy calibration. As an extreme
example, one or two frequently cited papers in my field from the 2
At this juncture, I'd like to bring up a "rule" I've made for myself regarding
data quality and smoothing: I'd rather walk away from a beam run with one good
spectrum than a hundred poor ones.
Meaning, for me anyway, if the data aren't smooth enough on their own, I'd
rather spend more precious
Hi all,
I have a small selection of x-ray books I'm happy to give you if you want them.
Please contact me privately if you do. I'd rather give them away to a good home
than send them to book heaven.
Koningsberger and Prins, X-Ray Absorption
Attwood, Soft X-rays and Extreme Ultraviolet Radiatio
The short, short version, in my estimation, is "pick two paths as a reasonable
starting point and let the fitting parameters do the rest." You could even use
two clones of the same path, which will end up getting different CNs, delr, and
ss in the fit.
There's no law that says you have to use F
, it showed things work in principle.
>
> The data, including a remeasured set of standards, is still available as the
> EXAFS Divination Set.
>
> Best,
>
> Scott Calvin
> Lehman College of the City University of New York
>
>> On Tue, Aug 13, 2019 at 9:41 PM Mi
an the
> individual who is seeking the answer to a different question.
>
> The most likely way to approach this problem is to both have the same
> background information about the sample(s) and to mutually determine what
> question you are trying to answer.
>
> Cheers,
>
e-analyzing the same data." Of
course, he's a strictly computational guy, so I'm not sure he necessarily has
standing to criticize...(Good-natured sarcasm font...)
> On Aug 13, 2019, at 6:43 PM, Anatoly Frenkel
> wrote:
>
> Are they equally smart?
>
> A
his?" So I thought I'd ask.
Your thoughts and experiences would be welcome. Thanks!
Mike Massey
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Hi Vineetha,
I am aware of some people doing (or at least attempting) multi-species
shell-by-shell fits, but it's a pretty daunting task, depending on your system.
Another approach that some people have had success with (check papers by Martin
McBriarty and colleagues) is a combination of LCF
A couple of thoughts...
A) If I were approaching a problem like this, I would probably prepare a
series of samples with different ratios, and look for trends in the fits.
If you see consistent differences across the series, in the same direction,
you can probably be more confident in the resulting
ed and the same approach to normalization is used, I don’t know if
> LCF would improve.
>
> Chris
>
>
>> On Jan 15, 2019, at 8:23 PM, Mike Massey wrote:
>>
>> Hi Scott,
>>
>>
>> I collect up to 2240 eV often, because that's about where th
ted samples, I don't have a problem.
Thanks,
Mike
> On Jan 15, 2019, at 5:12 PM, Scott Calvin wrote:
>
> Hi Mike,
>
> Is there a reason the data stops at 2200 eV—e.g., is there another edge just
> above that?
>
> —Scott
>
>> On Jan 15, 2019, at
to me like the post edge line is not
> in the right place. You need to tune it by hand when you have such a short
> energy range after the edge since the normalization is critically dependent
> on how you set this line.
>
> carlo
>
>> On Tue, 15 Jan 2019, Mike Massey wrote
Thanks for the response!
I should clarify, the data are collected in fluorescence, concentration is
perhaps in the hundreds of ppm to tenths-of-percent range in this case.
Personally I haven't had great luck with self-absorption correction in the past
(actually I've had basically no luck), so f
Just in case this might help...
"Dear Maintainers of Ifeffit,
I would like to use the 32-bit version of the application. Would you mind
posting a 32-bit version of the installation application?
Thank you very much."
> On Aug 22, 2018, at 9:25 PM, 天田雄大 wrote:
>
> Ifeffit管理者様
>
> 32ビット版ア
gt;
> Hi Mike,
>
>> On Thu, Aug 9, 2018 at 10:04 PM Mike Massey wrote:
>> This is interesting. Could you say more about your skepticism of the
>> robustness of EXAFS LCF, Matt?
>>
>> To be fair, it suffers from many of the same drawbacks of XANES LCF, plus
>>
This is interesting. Could you say more about your skepticism of the robustness
of EXAFS LCF, Matt?
To be fair, it suffers from many of the same drawbacks of XANES LCF, plus
others. But I'm curious about your thoughts on it since yours seems to be what
amounts to a "strong opinion" on the subje
* this list contains 221 atoms
> * x y z ipot tag distance
> 0.00.00.0 0 Fe1 0.0
>0.0 0.01.94335 4 C1.11.94335
>
> Thanks a lot for your help again!
>
> Best,
>
> Yun
I definitely recommend combining multiple atoms of similar distances into the
same path. That's what you end up with anyway if you use multiple paths, with a
lot more potential problems in the software.
Sometimes it is beneficial to split a shell of of atoms into two, to capture
some physical b
ugh information to
> replicate your problem on my own computer. I can only give a good answer
> when asked a good question.
>
> B
>
>
>
> On 10/15/2016 04:06 PM, Mike Massey wrote:
>
>> Hi everyone,
>>
>>
>> Apologies if this has been covered be
the
> normalized data.
>
> Anatoly Frenkel
> Stony Brook University
>
>
>> On Oct 15, 2016 4:10 PM, "Mike Massey" wrote:
>> Hi everyone,
>>
>>
>> Apologies if this has been covered before, I'm just getting around to
>>
Hi everyone,
Apologies if this has been covered before, I'm just getting around to upgrading
to Demeter. I have a bunch of old project files with a mishmash of data from
different sources, and I'm having trouble getting them to work fully with the
new software.
Any group with a data type of "
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