no i have calculated correctly because the convergence is good with higher k points<div>second is that i have tested zns,wc,NiAs phase none of them have less enthalpy at 130 gpa</div><div>other thing is that it is stable at above 250 gpa</div>
<div><br><br><div class="gmail_quote">On Wed, Aug 24, 2011 at 7:38 PM, Mike Mehl <span dir="ltr"><<a href="mailto:Michael.Mehl@nrl.navy.mil">Michael.Mehl@nrl.navy.mil</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex;">
If the B1 structure is unstable with respect to the B2 structure above<br>
130 GPa, but the B2 structure is dynamically unstable at and above 130<br>
GPa, there are two possible conclusions:<br>
<br>
1) The phonons for the B2 structure were not calculated accurately, or<br>
<br>
2) There is a competing structure that is lower in enthalpy than B1 or<br>
B2 at 130 GPa<br>
<br>
Without more information, no one can judge which conclusion is correct,<br>
suggest remedies for 1), or possible structure for 2).<br>
<div><div></div><div class="h5"><br>
<br>
On 08/23/2011 02:40 PM, bhabya sahoo wrote:<br>
> sir<br>
> i am calculating the phase transition of some carbides<br>
> the transition from B1 to B2 transition occures at 130 gpa by enthalpy<br>
> compparison<br>
> but i am able to find phonon instability at 130 gpa for B1 structure<br>
> but at the same time i am not able to find the dyanamic stability of B2<br>
> phase<br>
> but it occures high pressure (more than130 gpa )<br>
> is there any explanation for this ?<br>
><br>
> is there any relation of thermodyanamical unstability<br>
> and dyanamical unstability simultaneously?<br>
><br>
><br>
> answers are highly appriceted with some reson<br>
><br>
><br>
><br>
><br>
><br>
><br>
><br>
><br>
> Bd sahoo<br>
> reserch scholar<br>
> barc mumbai<br>
><br>
><br>
><br>
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<br>
</div><font color="#888888">--<br>
Michael J. Mehl<br>
Head, Center for Computational Materials Science<br>
Naval Research Laboratory Code 6390<br>
Washington DC<br>
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