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<body class='hmmessage'><div dir='ltr'>Dear all,<div><br></div><div>I am trying to optimize a structure I am working on. Firstly, I try to find what is the lattice constant that gives the minimum energy. When this value is used and an scf calculation is performed, The pressure is not exactly zero ( ~ - 2.45 Kbars) and the forces on individual atoms are still large. So I try to relax the structure using calculation =' relax'., which works pretty fine. However, due to the differences in the scf calculation performed by 'relax' and by 'scf', I again get a pressure of -2.45 and a large force when I run an scf calculation. I also realized that P ~ 0 and forces are pretty low at a value of the lattice constant different from the one above (which gives the minimum energy). Can anyone tell me what can be done? how can i get low forces keeping the equilibrium lattice constant intact? Is it possible to use a lattice constant which does give a minimum energy structure but retains both P and Forces almost zero?</div><div><br></div><div><span style="font-size: 12pt;">Any advice is highly appreciated.</span></div><div><span style="font-size: 12pt;"><br></span></div><div><span style="font-size: 12pt;">Elio</span></div><div><span style="font-size: 12pt;">Derby university </span></div><div><br></div> </div></body>
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