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<font face="Courier New" style="color: rgb(42, 42, 42); background-color: rgb(255, 255, 255); ">Dear all,</font><div style="line-height: 17px; color: rgb(42, 42, 42); font-family: 'Segoe UI', Tahoma, Verdana, Arial, sans-serif; background-color: rgb(255, 255, 255); "><font face="Courier New" style="line-height: normal; "><br style="line-height: 17px; "></font></div><div style="line-height: 17px; color: rgb(42, 42, 42); font-family: 'Segoe UI', Tahoma, Verdana, Arial, sans-serif; background-color: rgb(255, 255, 255); "><font face="Courier New" style="line-height: normal; ">I am trying to do el-ph calculations only at the Gamma point for graphene (as I want to compare it to another system where the calculations are only feasible at the Gamma point). However the values I am getting for lambda for graphene AT THE GAMMA POINT are :</font></div><div style="line-height: 17px; color: rgb(42, 42, 42); font-family: 'Segoe UI', Tahoma, Verdana, Arial, sans-serif; background-color: rgb(255, 255, 255); "><br></div><div style="line-height: 17px; color: rgb(42, 42, 42); font-family: 'Segoe UI', Tahoma, Verdana, Arial, sans-serif; background-color: rgb(255, 255, 255); "><p class="ecxMsoPlainText" style="margin-bottom: 1.35em; "><span lang="PT-BR" style="font-family: 'Courier New'; ">degauss lambda </span></p><p class="ecxMsoPlainText" style="margin-bottom: 1.35em; "><span lang="PT-BR" style="font-family: 'Courier New'; "> 0.005 13.442600 </span></p><p class="ecxMsoPlainText" style="margin-bottom: 1.35em; "><span lang="PT-BR" style="font-family: 'Courier New'; "> 0.015 2.303600 </span></p><p class="ecxMsoPlainText" style="margin-bottom: 1.35em; "><span lang="PT-BR" style="font-family: 'Courier New'; "> 0.020 1.756000</span><span style="font-family: 'Courier New'; font-size: 10pt; "> </span><span style="font-family: 'Courier New'; font-size: 10pt; "> </span></p><p class="ecxMsoPlainText" style="margin-bottom: 1.35em; "><span lang="PT-BR" style="font-family: 'Courier New'; "> 0.025 1.436000 </span></p><p class="ecxMsoPlainText" style="margin-bottom: 1.35em; "><span lang="PT-BR" style="font-family: 'Courier New'; "> 0.030 1.228800 </span></p><p class="ecxMsoPlainText" style="margin-bottom: 1.35em; "><span lang="PT-BR" style="font-family: 'Courier New'; "> 0.035 1.085800 </span></p><p class="ecxMsoPlainText" style="margin-bottom: 1.35em; "><span lang="PT-BR" style="font-family: 'Courier New'; "> 0.040 0.983000 </span></p><p class="ecxMsoPlainText" style="margin-bottom: 1.35em; "><span lang="PT-BR" style="font-family: 'Courier New'; "> 0.045 0.906400 </span></p><span lang="PT-BR" style="line-height: 18px; font-size: 10.5pt; font-family: 'Courier New'; "> 0.050 0.847800</span></div><div style="line-height: 17px; color: rgb(42, 42, 42); font-family: 'Segoe UI', Tahoma, Verdana, Arial, sans-serif; background-color: rgb(255, 255, 255); "><span style="line-height: 18px; font-family: 'Courier New'; font-size: 10.5pt; ">I am using a 90 x90 x1 grid (in scf) for graphene and the ph file has only one point nq1=0 nq2=0, nq3=0 (the Gamma point).</span></div><div style="line-height: 17px; color: rgb(42, 42, 42); font-family: 'Segoe UI', Tahoma, Verdana, Arial, sans-serif; background-color: rgb(255, 255, 255); "><span style="line-height: 18px; font-family: 'Courier New'; font-size: 10.5pt; "><br></span></div><div style="line-height: 17px; color: rgb(42, 42, 42); font-family: 'Segoe UI', Tahoma, Verdana, Arial, sans-serif; background-color: rgb(255, 255, 255); "><span style="line-height: 18px; font-family: 'Courier New'; font-size: 10.5pt; ">It is already known that lambda for graphene is ~0.02. </span></div><div style="line-height: 17px; color: rgb(42, 42, 42); font-family: 'Segoe UI', Tahoma, Verdana, Arial, sans-serif; background-color: rgb(255, 255, 255); "><span style="line-height: 18px; font-family: 'Courier New'; font-size: 10.5pt; ">(1) Do the above results mean that one cannot calculate el-ph coefficients unless on a grid of phonons and then are the calculations -at the Gamma point ONLY- useless and unexact?</span></div><div style="line-height: 17px; color: rgb(42, 42, 42); font-family: 'Segoe UI', Tahoma, Verdana, Arial, sans-serif; background-color: rgb(255, 255, 255); "><span style="line-height: 18px; font-family: 'Courier New'; font-size: 10.5pt; "><br></span></div><div style="line-height: 17px; color: rgb(42, 42, 42); font-family: 'Segoe UI', Tahoma, Verdana, Arial, sans-serif; background-color: rgb(255, 255, 255); "><span style="line-height: 18px; font-family: 'Courier New'; font-size: 10.5pt; ">(2) or does this mean that the results did not converge due to a small k-mesh in the scf calculations (90x90x1) and I need to increase it to say 400x400x1?</span></div><div style="line-height: 17px; color: rgb(42, 42, 42); font-family: 'Segoe UI', Tahoma, Verdana, Arial, sans-serif; background-color: rgb(255, 255, 255); "><span style="line-height: 18px; font-family: 'Courier New'; font-size: 10.5pt; "><br></span></div><div style="line-height: 17px; color: rgb(42, 42, 42); font-family: 'Segoe UI', Tahoma, Verdana, Arial, sans-serif; background-color: rgb(255, 255, 255); "><span style="line-height: 18px; font-family: 'Courier New'; font-size: 10.5pt; ">Any suggestions of any kind would also be ahighly appreciated.</span></div><div style="line-height: 17px; color: rgb(42, 42, 42); font-family: 'Segoe UI', Tahoma, Verdana, Arial, sans-serif; background-color: rgb(255, 255, 255); "><span style="line-height: 18px; font-family: 'Courier New'; font-size: 10.5pt; "><br></span></div><div style="line-height: 17px; color: rgb(42, 42, 42); font-family: 'Segoe UI', Tahoma, Verdana, Arial, sans-serif; background-color: rgb(255, 255, 255); "><span style="line-height: 18px; font-family: 'Courier New'; font-size: 10.5pt; ">Thanks for your help</span></div><div style="line-height: 17px; color: rgb(42, 42, 42); font-family: 'Segoe UI', Tahoma, Verdana, Arial, sans-serif; background-color: rgb(255, 255, 255); "><span style="line-height: 18px; font-family: 'Courier New'; font-size: 10.5pt; "><br></span></div><div style="line-height: 17px; color: rgb(42, 42, 42); font-family: 'Segoe UI', Tahoma, Verdana, Arial, sans-serif; background-color: rgb(255, 255, 255); "><span style="line-height: 18px; font-family: 'Courier New'; font-size: 10.5pt; ">Elie M</span></div><div style="line-height: 17px; color: rgb(42, 42, 42); font-family: 'Segoe UI', Tahoma, Verdana, Arial, sans-serif; background-color: rgb(255, 255, 255); "><span style="line-height: 18px; font-family: 'Courier New'; font-size: 10.5pt; ">University of Notts</span></div><div style="line-height: 17px; color: rgb(42, 42, 42); font-family: 'Segoe UI', Tahoma, Verdana, Arial, sans-serif; background-color: rgb(255, 255, 255); "><span style="line-height: 18px; font-family: 'Courier New'; font-size: 10.5pt; ">NG7 2RD</span></div><div style="line-height: 17px; color: rgb(42, 42, 42); font-family: 'Segoe UI', Tahoma, Verdana, Arial, sans-serif; background-color: rgb(255, 255, 255); "><span style="line-height: 18px; font-family: 'Courier New'; font-size: 10.5pt; ">UK</span></div> </div></body>
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