<html><body><div style="color:#000; background-color:#fff; font-family:garamond, new york, times, serif;font-size:14pt"><div><span></span></div><div style="font-family: garamond,new york,times,serif; font-size: 14pt;"><div style="font-family: times new roman,new york,times,serif; font-size: 12pt;"><div id="yiv947442280"><div><div style="color: rgb(0, 0, 0); background-color: rgb(255, 255, 255); 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="yiv947442280misspell-1" class="yiv947442280mark">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="yiv947442280misspell-2" class="yiv947442280mark">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="yiv947442280result_box" class="yiv947442280long_text yiv947442280short_text" lang="en"><span class="yiv947442280hps">================<br></span></span></font></div><div style="color: rgb(162, 162, 162); font-family: garamond,new york,times,serif;"><font size="4"><span id="yiv947442280result_box" class="yiv947442280long_text yiv947442280short_text" lang="en"><span class="yiv947442280hps"><span id="yiv947442280misspell-3" class="yiv947442280mark">Sakhraoui</span> <span id="yiv947442280misspell-4"
class="yiv947442280mark">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="yiv947442280result_box" class="yiv947442280long_text yiv947442280short_text" lang="en"><span class="yiv947442280hps"><span id="yiv947442280misspell-5" class="yiv947442280mark">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="yiv947442280result_box" class="yiv947442280long_text yiv947442280short_text" lang="en"><span class="yiv947442280hps">F</span></span><span id="yiv947442280result_box" class="yiv947442280long_text yiv947442280short_text" lang="en"><span class="yiv947442280hps"><span id="yiv947442280misspell-6" class="yiv947442280mark">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="yiv947442280result_box" class="yiv947442280long_text yiv947442280short_text" lang="en"><span class="yiv947442280hps"><span id="yiv947442280misspell-7" class="yiv947442280mark">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="yiv947442280result_box" class="yiv947442280long_text yiv947442280short_text" lang="en"><span class="yiv947442280hps">================</span></span></font></div></div></div></div><br><br> </div> </div> </div></body></html>