nd{eqnarray*}">
<BR CLEAR="ALL"></DIV><P></P>
<BR CLEAR="ALL"><P></P>
<BR CLEAR="ALL"><P></P>
We know this is NOT the correct Becke prescribed implementation which
requires the XC potential in the energy expression.  But this is what
is currently implemented as an approximation to it.

<P>
The keyword <code>acm</code> specifies that the exchange-correlation energy
is computed as
<P></P>
<DIV ALIGN="CENTER">
<!-- MATH
 \begin{eqnarray*}
E_{XC} \ &=& \ a_0 E^{\rm HF}_X + (1-a_0) E^{\rm Slater}_{X} +
a_X \Delt