<html><body><div style="color:#000; background-color:#fff; font-family:tahoma, new york, times, serif;font-size:18pt"><div>dear all, <br></div><div style="color: rgb(0, 0, 0); font-size: 24px; font-family: tahoma,new york,times,serif; background-color: transparent; font-style: normal;">i do surface calculation with pw.x, i want to estimate the C value in the <span id="misspell-1" class="mark">tetragonal</span> structure, </div><div style="color: rgb(0, 0, 0); font-size: 24px; font-family: tahoma,new york,times,serif; background-color: transparent; font-style: normal;">after <span id="misspell-2" class="mark">scf</span> calculation i find that many values of C have the same energy which you can see it in the figure.</div><div style="color: rgb(0, 0, 0); font-size: 24px; font-family: tahoma,new york,times,serif; background-color: transparent; font-style: normal;">thanks</div><div style="color: rgb(162, 162, 162); font-family: garamond,new
york,times,serif;"><font size="4"><span id="yiv1104861945result_box" class="yiv1104861945long_text yiv1104861945short_text" lang="en"><span class="yiv1104861945hps">================<br></span></span></font></div><div style="color: rgb(162, 162, 162); font-family: garamond,new york,times,serif;"><font size="4"><span id="yiv1104861945result_box" class="yiv1104861945long_text yiv1104861945short_text" lang="en"><span class="yiv1104861945hps"><span id="misspell-3" class="mark">Sakhraoui</span> <span id="misspell-4" class="mark">Taoufik</span></span></span></font></div><div style="color: rgb(162, 162, 162); font-family: garamond,new york,times,serif;"><font size="4"><span id="yiv1104861945result_box" class="yiv1104861945long_text yiv1104861945short_text" lang="en"><span class="yiv1104861945hps"><span id="misspell-5" class="mark">LMCN</span></span></span></font></div><div style="color: rgb(162, 162, 162); font-family: garamond,new york,times,serif;"><font
size="4"><span id="yiv1104861945result_box" class="yiv1104861945long_text yiv1104861945short_text" lang="en"><span class="yiv1104861945hps">F</span></span><span id="yiv1104861945result_box" class="yiv1104861945long_text yiv1104861945short_text" lang="en"><span class="yiv1104861945hps"><span id="misspell-6" class="mark">aculty</span> of science <br></span></span></font></div><div style="color: rgb(162, 162, 162); font-family: garamond,new york,times,serif;"><font size="4"><span id="yiv1104861945result_box" class="yiv1104861945long_text yiv1104861945short_text" lang="en"><span class="yiv1104861945hps"><span id="misspell-7" class="mark">Monastir</span>, Tunisia</span></span></font></div><div style="color: rgb(162, 162, 162); font-family: garamond,new york,times,serif;"><font size="4"><span id="yiv1104861945result_box" class="yiv1104861945long_text yiv1104861945short_text" lang="en"><span
class="yiv1104861945hps">================</span></span></font></div></div></body></html>