 the first derivative forms (normalised to &ndash;1 when E=1,
if reasonable):

<P>
0 : Woods-Saxon  = - P1 * 4 * E / (1+E)<SPAN CLASS="MATH"><IMG
 STYLE=""
 SRC="img37.svg"
 ALT="$^2$"></SPAN> 
<BR>
1 : WS squared   = - P1 * 8 * E*E / (1+E)<SPAN CLASS="MATH"><IMG
 STYLE=""
 SRC="img87.svg"
 ALT="$^3$"></SPAN>
<BR>
2 : Gaussian     = - P1 * 2 * exp(-RH*RH) * RH
<BR>
3 : Yukawa       = - P1 * E * (1 + r/P3) / (r*r)
<BR>
4 : Exponential  = - P1 * E
<BR>
5 : Reid soft core for <SPAN CLASS="MATH"><IMG
 STYLE=""
