RE>
styles:
</PRE>
<UL>
    <LI>
    geometric = sqrt(i*j) for both epsilon and sigma 
    <LI>
    arithmetic = sqrt(i*j) for epsilon, (i+j)/2 for sigma 
    <LI>
    sixthpower = see force_fields file for details 
</UL>
<PRE>
determine the kind of mixing rule that is applied to generate nonbond
  coefficients for interactions between type i and type j atoms
mixing rules are applied only when nonbond coeffs are input in a &quot;read data&quot; file
for nonbond style "soft", only epsilons (prefactor A) are 