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<div class="moz-cite-prefix">OK. Now I better understand your
question. <br>
Indeed the magnetic ordering is playing an essential role in the
temperature dependence of Mossbauer parameters. <br>
<span id="ecxresult_box" lang="en"><span><br>
Switching to TEMP with a fixed value will not help you in the
present case, because you must consider the temperature effect
by calculating the Mossbauer parameters for the
antiferromagnetic low temperature magnetic order and the
paramagnetic room temperature one. However, we cannot do a
calculation for a paramagnetic order (which is dynamic). <br>
<br>
Some years ago we had a similar problem for the modelling of
the temperature effect of optical and magnetic properties of
CuO. It was not so different to your problem except that the
Neel temperature is significantly higher (TN = 230 K). We were
able to reproduce the evolution of the electric field gradient
(deduced from NMR exp.) by considering "snapshots" of the
magnetic phases of CuO in which magnetic disorder were
created. Our strategy was thus to neglect the dynamical
effects of the temperature and to consider only the
progressive growth of magnetic disorder in CuO. It was a very
efficient approximation which were able to reproduce not only
the temperature effect on the magnetic and EFG data, but also
the optical properties. <br>
<br>
Here is the reference of this paper. I hope it can help you. <br>
<br>
<a class="moz-txt-link-freetext" href="http://iopscience.iop.org/0953-8984/22/4/045502/">http://iopscience.iop.org/0953-8984/22/4/045502/</a><br>
<br>
Best Regards<br>
<br>
Xavier<br>
P.S.: If you need I can send you a PDF copy of the paper. <br>
<br>
<br>
<br>
<br>
</span></span><br>
<br>
Le 7/17/2013 10:32 AM, abdel Mar.. a écrit :<br>
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<div dir="ltr">thank you Xavier for your replay<br>
<br>
<span id="result_box" lang="en"><span class="hps">As you know </span>
<span class="hps">Mossbauer</span> <span class="hps">parameters
vary</span> <span class="hps atn">with temperature</span><span
class="hps"></span><br>
<span class="hps">my</span> <span class="hps">Mossbauer</span>
<span class="hps">parameters are measured</span> <span
class="hps">at room temperature.</span><br>
<span class="hps">how can</span> <span class="hps">we</span>
<span class="hps">relate this</span> <span class="hps atn">measure
(</span><span>at room</span> <span class="hps">temperature)</span>
<span class="hps">to</span> <span class="hps">the calculated</span>
<span class="hps">value</span> <span class="hps">at</span> <span
class="hps atn">(</span><span>0k</span><span>)</span></span>.<br>
<br>
for example : my material is paramagnetic at room temperature,
antiferromagnetic at low temperature < 30K.<br>
my measure is at room temperature, so my calculation will be for
antiferro. case. i'm lost at this stage<img
moz-do-not-send="true" src="https://a.gfx.ms/Emoji_1F629.png"
alt="Emoji" class="Emoji$1F629$ABA RenderedEmoji"><br>
<br>
Regards<br>
A<br>
<br>
<div>
<hr id="stopSpelling">Date: Wed, 17 Jul 2013 09:57:19 +0200<br>
From: <a class="moz-txt-link-abbreviated" href="mailto:xavier.rocquefelte@cnrs-imn.fr">xavier.rocquefelte@cnrs-imn.fr</a><br>
To: <a class="moz-txt-link-abbreviated" href="mailto:wien@zeus.theochem.tuwien.ac.at">wien@zeus.theochem.tuwien.ac.at</a><br>
Subject: Re: [Wien] temperature influence on EFGs calculations<br>
<br>
<div class="ecxmoz-cite-prefix">Which temperature effect do
you want to consider? <br>
Indeed, the effect of temperature on the atomic structure is
usually the more important one for EFGs... <br>
Thus one way to consider the temperature effect on these
properties is simply to consider different atomic structures
refined for different temperatures (volume expansion...). <br>
<br>
Best Regards<br>
<br>
Xavier<br>
<br>
<br>
<br>
Le 7/17/2013 9:44 AM, abdel Mar.. a écrit :<br>
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<div dir="ltr"><span id="ecxresult_box" lang="en"><span
class="ecxhps"></span>Dear Wien2k users<br>
<span class="ecxhps"><br>
is</span> <span class="ecxhps">there a</span> <span
class="ecxhps">way to</span> <span class="ecxhps">include
the </span><span class="ecxhps"> temperature effetc in
the</span> <span class="ecxhps">calculation of the</span>
<span class="ecxhps">Mossbauer</span> <span
class="ecxhps">parameters </span>( <span
class="ecxhps">EFGs, RTO)</span><span>.</span><br>
<span class="ecxhps"><br>
may be</span> <span class="ecxhps">with</span> <span
class="ecxhps">in</span> <span class="ecxhps">case.in2</span><span>?</span><span>:
with switching to TEMP with a fixed value?</span><br>
<span class="ecxhps">TEMP</span> <span class="ecxhps">0000</span>
<span class="ecxhps ecxatn">(</span><span>GAUSS</span><span>,</span>
<span class="ecxhps">ROOT,</span> <span class="ecxhps">TEMP</span><span>,</span>
<span class="ecxhps">TETRA</span><span>,</span> <span
class="ecxhps">ALL</span> <span class="ecxhps">eval)<br>
<br>
Best regards<br>
<br>
A<br>
<br>
<br>
</span></span> </div>
<br>
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