Cut-off radius in the inverse-12 (I12) purely repulsive potential, which can be used
as a reference model for adiabatic switching simulations.

<p>
&Phi;(r) = <tt>I12_epsilon</tt> &sdot; (<tt>I12_sigma</tt> / r)<sup>12</sup>
 &nbsp; (if r < <tt>I12_rc</tt>)

<p>
Also see <tt>runMDSWITCH</tt>, <tt>runMCSWITCH</tt>.

