br>
<i>Optional</i><br>
Default: 0<br><br>
Sets the number of states considered as core in &lt;&Sigma;<sub>x</sub>-<i>v</i><sub>xc</sub>&gt. This options is meant to mimic the pseudopotential approximation.</li><br>
<hr>
<a name=ecp_small_basis><li>                 <span style="display:inline-block;background:#EEEEEE;width:400px">               <b>ecp_small_basis</b>  </span>  
<b><font color="red">EXPERIMENTAL</font> </b> 
<br><br>
<i>Optional</i><br>
Default: none<br><br>
Calls for a smaller basis set use