<html><body bgcolor="#FFFFFF"><div>Dear Reza,<br></div><div><br>Le 13-set-2010 à 20:49, reza shidpoor <<a href="mailto:rezashidpoor@gmail.com">rezashidpoor@gmail.com</a>> a écrit :<br><br></div><div></div><blockquote type="cite"><div><br clear="all">Dear Gabriele<br><br>Thank you for your comments in pwscf forum.<br><br>I performed your suggestion that ecut is set to 32 Ry. The structure was relaxed </div></blockquote><div><br></div><div>So you can confirm that with this cutoff it works, do you?</div><div><br></div><br><blockquote type="cite"><div>and I repeated with ecut=20 , 22 Ry.<br></div></blockquote><div><br></div><div>Why do you want to do so?</div><div><br></div><div>If the cutoff id too low the forces are not described correctly and the ralaxation algorithm might fail to converge.</div><br><blockquote type="cite"><div>It seems that the structure did not relaxed with this point "<br>
<i><br> .............<br> ...........<br> the Fermi energy is -5.0636 ev<br><br>! total energy = -262.94392529 Ry<br> Harris-Foulkes estimate = -262.94392533 Ry<br> estimated scf accuracy < 0.00000006 Ry<br>
<br> The total energy is the sum of the following terms:<br><br> one-electron contribution = -323.90644330 Ry<br> hartree contribution = 178.85727642 Ry<br> xc contribution = -104.02662243 Ry<br>
ewald contribution = -13.85257067 Ry<br> smearing contrib. (-TS) = -0.01556530 Ry<br><br> convergence has been achieved in 2 iterations<br><br> Forces acting on atoms (Ry/au):<br><br><br>
negative rho (up, down): 0.998E-04 0.000E+00<br> atom 1 type 1 force = 0.00000000 0.00223711 0.00000000<br> atom 2 type 1 force = -0.00165978 -0.00111856 0.00000000<br> atom 3 type 1 force = 0.00165978 -0.00111856 0.00000000<br>
<br> Total force = 0.003608 Total SCF correction = 0.000988<br> SCF correction compared to forces is too large, reduce conv_thr<br></i></div></blockquote><div><br></div><div>Besides increasing the cutoff, you might need to decrease this threshold on order for the forces to be perfectly consistent with the total energy.</div><div><br></div><br><blockquote type="cite"><div><i><br> The maximum number of steps has been reached.<br><br> End of BFGS Geometry Optimization<br>
Begin final coordinates<br><br>ATOMIC_POSITIONS (angstrom)<br>Au 0.000000000 0.248435531 0.000000000<br>Au -2.339313337 1.325352234 0.000000000<br>Au 2.339313337 1.325352234 0.000000000<br>End final coordinates</i><br>
<br>........................<br>........................<br><br>Questions :<br><br>1) The electron_maxstep is equaled 100. What is purpose of "number of states" ?</div></blockquote><div><br></div>???<div>You are confusing number of states with number of electrpnic steps and perhaps also with ionic steps. Please spend some time reading the manual and some examples or tutorials.</div><div><br><blockquote type="cite"><div><br>2) Should I consider system to be semiconducting If I want to simulate 4-atoms cluster?<br></div></blockquote><div><br></div>If you are not sure, you can treat your system as metallic with a small smearing and then, if it turns out to have a gap, reduce/remove the smearing.</div><div><br></div><div> GS<br><blockquote type="cite"><div>
<br><br>Best Regards,<br>Reza.Shidpour<br>SUT<br>
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