<div>Dear Michael Mehl,</div>
<div>I have read the two papers</div>
<div><a href="http://cst-www.nrl.navy.mil/users/mehl/papers/cij453.pdf" target="_blank">http://cst-www.nrl.navy.mil/users/mehl/papers/cij453.pdf</a><br><br>and<br><br>Phys. Rev. B 47, 2493 (1993)<br>, </div>
<div>But my question is, they have given only two equation, and our unknown quantity are 3 (C11, C12, and C44). So can we find three unknown quantity from two equations acuratelly.</div>
<div><br><br> </div>
<div class="gmail_quote">On Thu, Jul 16, 2009 at 10:27 PM, Michael Mehl <span dir="ltr"><<a href="mailto:rcjhawk@gmail.com" target="_blank">rcjhawk@gmail.com</a>></span> wrote:<br>
<blockquote class="gmail_quote" style="PADDING-LEFT: 1ex; MARGIN: 0px 0px 0px 0.8ex; BORDER-LEFT: #ccc 1px solid">
<div>Bipul Rakshit wrote:<br><br>> Because in order to calculate 3 elastic constants (C11, C12 and C44) we<br>> require 3 equations, so do I have to use the above three equations, both<br>> type (volume conservative and non-conservative) to calculate a single<br>
> set of elastic constants?<br><br></div>Yes.<br>
<div><br>><br>> please guide me for the same.<br><br></div>You'll have to compute the bulk modulus at same volume that you use to<br>compute C44 and C11-C12. In a cubic system B = (C11+2 C12)/3, giving<br>you enough information to get all three elastic constants at that volume.<br>
<br>There are many, many programs that will compute B(V), see this list's<br>archives for details.<br><br>My favorite reviews of the subject are:<br><br><a href="http://cst-www.nrl.navy.mil/users/mehl/papers/cij453.pdf" target="_blank">http://cst-www.nrl.navy.mil/users/mehl/papers/cij453.pdf</a><br>
<br>and<br><br>Phys. Rev. B 47, 2493 (1993)<br><br>but I may be somewhat biased.<br><font color="#888888"><br>--<br>Michael J. Mehl, Naval Research Laboratory, Washington DC<br>On Sabbatical at Duke University until 31 July 2009<br>
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<div></div><br>-- <br>Bipul Rakshit<br>PhD Student, <br>Barkatullah University,<br>Bhopal 462026,<br>MP, India<br>