<div dir="ltr">Hi,<br><br>given this amount of information I can only suggest to try mulliken instead of mulliken_charges and to use a wavefunction converged with U=0 as an initial guess.<br><br>Matthias<br><br>On Sunday, March 2, 2014 8:03:19 PM UTC+1, roben nano wrote:<blockquote class="gmail_quote" style="margin: 0;margin-left: 0.8ex;border-left: 1px #ccc solid;padding-left: 1ex;"><div dir="ltr"><div style="text-align:left" dir="ltr"><span lang="en"><span><br><font size="2">Hello,</font></span><font size="2"> <br><br><span>help</span> <span>me to solve</span> <span>this problem, when</span> <span>I start to</span> <span>optimize the</span> <span>cell is</span> <span>using</span> <span>DFT</span> <span>+</span> <span>U</span><span>, I get</span> <span>this</span> <span>message:</span> <br>
<span>"</span><span>***</span> <span>WARNING</span> <span>1:52:02 p.m.</span> <span>in</span> <span>dft_plus_u</span><span>:</span> <span>DFT</span> <span>+</span> <span>U</span> <span>::</span> <span>mulliken_charges</span> <span>energy</span> <span>***</span> <br>
  <span>Contibution</span> <span>is</span> <span>***</span> <span>Possibly</span> <span>due</span> <span>to</span> <span>unphysical</span> <span>negative</span> <span>Mulliken</span> <span>charge</span><span>.</span> <span>***</span> <br>
  <span>***</span> <span>Check your</span> <span>input</span><span>,</span> <span>if</span> <span>this</span> <span>warning</span> <span>Persists</span> <span>or</span> <span>try</span> <span>a different</span> <span>method</span><span>!</span> <span>***</span> <span>'</span><br>
<span>knowing that</span> <span>I use the</span> <span>following</span> <span>bases</span> <span>and potential</span> <br>    <span>BASIS_SET</span> <span>DZVP</span><span>-</span><span>MOLOPT</span><span>-SR-</span><span>GTH</span> <br>
    <span>POTENTIAL</span> <span>GTH-</span><span>PADE</span><span>-</span><span>q12</span> <br><br><span>thank you</span> <span>in advance</span></font></span></div></div></blockquote></div>