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<body class='hmmessage'><div dir='ltr'>Hello all,<div><br></div><div>I am still having a problem with relaxing a structure (hexagonal).. The initial pressure was calculated to be -12 kbars. I managed to reduce the pressure to 0.02 and the total force to 0.0007 using vc-relax. However when I ran a scf calculation on the relaxed structure , the pressure was again -16 and the total force 0.4. Professor Paolo G. gave me a link for this problem.. I understood that I need to increase the cutoff kinteic energy which I did and I realized that the pressure goes down but to -6; however the total force is still 0.4! </div><div><br></div><div>(1) Anyone knows how to solve this problem.</div><div><br></div><div>I have run the calculation again wih ibrav=0 instead of ibrav=6 and the crystal axes were:</div><div><br></div><div><div> a(1) = ( 0.492694 0.853319 0.000001 )</div><div> a(2) = ( 0.492685 -0.853314 -0.000001 )</div><div> a(3) = ( 0.000001 0.000004 4.274389 )</div></div><div><br></div><div>The pressure was -0.02 and the total force was 0.001 which was fine in both scf and vc-relax. However when I redid an scf calculation with ibrav=6 with c/a =4.274389 (which I read from the ibrav=0 calculation with the same atomic positions of the "ibrav=0" calculation), I still got P =-16 and total force=0.4. I was trying to convert the ibrav=0 input to ibrav=6..did I do anything wrong?</div><div><br></div><div><br></div><div>Any help would be appreciated </div><div><br></div><div>Thanks</div><div><br></div><div>Elio Nahdan</div><div><br></div> </div></body>
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