<html><head></head><body><div style="color:#000; background-color:#fff; font-family:HelveticaNeue, Helvetica Neue, Helvetica, Arial, Lucida Grande, Sans-Serif;font-size:16px"><div id="yiv5259059905yui_3_16_0_1_1445235245458_3379" class="">Dear Wien2k users,</div><div id="yiv5259059905yui_3_16_0_1_1445235245458_3379" class="">Can you guide me for finding equations of elastic constants under pressure?</div><div id="yiv5259059905yui_3_16_0_1_1445235245458_3379" class="">For example for cubic compounds and for finding C44 under strain as:</div><div id="yiv5259059905yui_3_16_0_1_1445235245458_3379" class=""> 1 delta 0</div><div id="yiv5259059905yui_3_16_0_1_1445235245458_3379" class=""> delta 1 0</div><div id="yiv5259059905yui_3_16_0_1_1445235245458_3379" class=""> 0 0 1/(1-delta^2)</div><div id="yiv5259059905yui_3_16_0_1_1445235245458_3379" class=""><br id="yui_3_16_0_1_1445400557621_2685" class=""></div><div id="yiv5259059905yui_3_16_0_1_1445235245458_3379" dir="ltr" class="">the equation will be as:</div><div id="yiv5259059905yui_3_16_0_1_1445235245458_3379" dir="ltr" class="">E(V,delta) = E(V0,0)+V0(2C44*delat^2 + O(delta^4))</div><div id="yiv5259059905yui_3_16_0_1_1445235245458_3379" dir="ltr" class=""><br id="yui_3_16_0_1_1445400557621_2690" class=""></div><div id="yiv5259059905yui_3_16_0_1_1445235245458_3379" dir="ltr" class=""><br id="yui_3_16_0_1_1445400557621_2693" class=""></div><div id="yiv5259059905yui_3_16_0_1_1445235245458_3379" dir="ltr" class="">and now, i would like to know how i must correct this equation or other equations under pressure.</div><div id="yiv5259059905yui_3_16_0_1_1445235245458_3379" dir="ltr" class="">Please guide me</div><div id="yiv5259059905yui_3_16_0_1_1445235245458_3379" dir="ltr" class=""><br id="yui_3_16_0_1_1445400557621_2698" class=""></div><div id="yiv5259059905yui_3_16_0_1_1445235245458_3379" dir="ltr" class="">Sincerely,</div><div id="yiv5259059905yui_3_16_0_1_1445235245458_3379" dir="ltr" class="">Amir</div></div></body></html>