<div dir="ltr"><div><div><div>Respected Sirs/Friends,<br></div>
I have optimised the anatase structure(vc-relax) by default bfgs
controlling parameters and with changed controlling parameters. Now I
got two different lattice parameters and forces as shown below.<br></div>For default values:<br>Total force = 0.000082 Total SCF correction = 0.000002<br>...................................................<br><br>CELL_PARAMETERS (alat= 6.97686888)<br> 1.016725684 -0.000000000 0.000000000<br> -0.000000000 1.016725684 0.000000000<br> 0.000000000 0.000000000 2.490647736<br><br></div>For Changed parameters:<br><br>The changed parameters are<br><br> &IONS<br> <br> ion_dynamics = 'bfgs' ,<br> trust_radius_max = 0.2D0 ,<br> trust_radius_min = 0.5D0 ,<br> trust_radius_ini = 0.1D0 ,<br><div><br>Total force = 0.014421 Total SCF correction = 0.000014<br>......................................................<br><br>CELL_PARAMETERS (alat= 6.97686888)<br> 1.011136738 0.000000000 0.000000000<br> 0.000000000 1.011136738 0.000000000<br> 0.000000000 0.000000000 2.543455379<br><br></div><div>Which
Lattice parameters I have to take for further calculations? And there
is a big difference in final force value for the structure where bfgs
controlling parameters are changed. In the input file I actually given
high convergence thresold value (conv_thr = 1.D-8) and default
forc_convr_thr values.<br></div>Is there any general procedure for doing optimization? If there please direct me towards the solution.<br><div><div class="gmail_signature" data-smartmail="gmail_signature"><div dir="ltr"><div><div dir="ltr"><div><div><div><div style="margin-left:40px;text-align:right"> With Regards,<br></div><div style="text-align:right">A.Suresh,<br></div></div><div style="text-align:right">Research Scholar,</div></div><div style="text-align:right">Madurai Kamaraj University,<br></div></div><div style="text-align:right">Madurai.<br></div></div></div></div></div></div>
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