out-of-plane 
</UL>
<PRE>
define style of improper interactions to use for all trigonal centers
in class2 case, dictates that angle-angle terms be included for all
  trigonal and tetrahedral centers
angle for harmonic is improper torsion, angle for class2 is Wilson out-of-plane
must be used before the &quot;read data&quot; command (if not using the
  default) to tell the program how to read the &quot;Improper
  Coeffs&quot; entry in the data file
can be used after the &quot;read data&quot; command to change