<table cellspacing="0" cellpadding="0" border="0" ><tr><td valign="top" style="font: inherit;">Dear All<br>Has anyone suitable reference about elastic constant matrix for Hexagonal lattice .<br>In principle does this elastic constants differ in each Hexagonal shape crystals?( I mean for example between <span>NiAs</span>-type material that has Hexagonal lattice and HCP lattice ) .<br>Another question: is any reffernce about how to connect the elestic constant of Hexagonal to phonon frequency?<br>Thanks a lot<br><br>Ali Kazempour<br>
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Fritz-Haber-Institut fax : ++49-30-8413 4701<br>
der Max-Planck-Gesellschaft<br>
Faradayweg 4-6 e-mail: kazempou@fhi-berlin.mpg.de<br>
D-14 195 Berlin-Dahlem / German</td></tr></table><br>