Fixed error in lj/gromacs

git-svn-id: svn://svn.icms.temple.edu/lammps-ro/trunk@6819 f3b2605a-c512-4ea7-a41b-209d697bcdaa

doc/Eqs/pair_gromacs.tex

@@ -7,8 +7,8 @@ E_{LJ} & = & 4 \epsilon \left[ \left(\frac{\sigma}{r}\right)^{12} -
                        \left(\frac{\sigma}{r}\right)^6 \right] + S_{LJ}(r)
                        \qquad r < r_c \\
 E_C & = & \frac{C q_i q_j}{\epsilon  r} + S_C(r) \qquad r < r_c \\
-S(r) & = & 0 \qquad r < r_1 \\
-S(r) & = & A (r - r_1)^2 + B (r - r_1)^3 \qquad  r_1 < r < r_c
+S(r) & = & C \qquad r < r_1 \\
+S(r) & = & \frac{A}{3} (r - r_1)^3 + \frac{B}{4} (r - r_1)^4 + C \qquad  r_1 < r < r_c
 \end{eqnarray*}                           
 
 \end{document}

doc/pair_gromacs.html

@@ -42,23 +42,24 @@ pair_coeff * * 100.0 2.0
 </PRE>
 <P><B>Description:</B>
 </P>
-<P>The <I>lj/gromacs</I> styles compute LJ and Coulombic interactions with an
-additional switching function S(r) that ramps the energy and force
+<P>The <I>lj/gromacs</I> styles compute shifted LJ and Coulombic interactions 
+with an additional switching function S(r) that ramps the energy and force
 smoothly to zero between an inner and outer cutoff.  It is a commonly
 used potential in the <A HREF = "http://www.gromacs.org">GROMACS</A> MD code and for
 the coarse-grained models of <A HREF = "#Marrink">(Marrink)</A>.
 </P>
 <CENTER><IMG SRC = "Eqs/pair_gromacs.jpg">
 </CENTER>
-<P>R1 is the inner cutoff; Rc is the outer cutoff.  The coefficients A
-and B are computed by LAMMPS to perform the smoothing.  The function
+<P>R1 is the inner cutoff; Rc is the outer cutoff.  The coefficients A, B, 
+and C are computed by LAMMPS to perform the shifting and smoothing.  
+The function
 S(r) is actually applied once to each term of the LJ formula and once
-to the Coulombic formula, so there are 2 or 3 sets of A,B coefficients
+to the Coulombic formula, so there are 2 or 3 sets of A,B,C coefficients
 depending on which pair_style is used.  The boundary conditions
 applied to the smoothing function are as follows: S(r1) = S'(r1) = 0,
-S(rc) = -F(rc), S'(rc) = -F'(rc), where F(r) is the correpsonding term
-in the LJ or Coulombic function and a single quote represents a
-derivative with respect to r.
+S(rc) = -F(rc), S'(rc) = -F'(rc), where F(r) is the corresponding term
+in the LJ or Coulombic potential energy function and a 
+single quote represents a derivative with respect to r.
 </P>
 <P>The inner and outer cutoff for the LJ and Coulombic terms can be the
 same or different depending on whether 2 or 4 arguments are used in

doc/pair_gromacs.txt

@@ -35,23 +35,24 @@ pair_coeff * * 100.0 2.0 :pre
 
 [Description:]
 
-The {lj/gromacs} styles compute LJ and Coulombic interactions with an
-additional switching function S(r) that ramps the energy and force
+The {lj/gromacs} styles compute shifted LJ and Coulombic interactions 
+with an additional switching function S(r) that ramps the energy and force
 smoothly to zero between an inner and outer cutoff.  It is a commonly
 used potential in the "GROMACS"_http://www.gromacs.org MD code and for
 the coarse-grained models of "(Marrink)"_#Marrink.
 
 :c,image(Eqs/pair_gromacs.jpg)
 
-R1 is the inner cutoff; Rc is the outer cutoff.  The coefficients A
-and B are computed by LAMMPS to perform the smoothing.  The function
+R1 is the inner cutoff; Rc is the outer cutoff.  The coefficients A, B, 
+and C are computed by LAMMPS to perform the shifting and smoothing.  
+The function
 S(r) is actually applied once to each term of the LJ formula and once
-to the Coulombic formula, so there are 2 or 3 sets of A,B coefficients
+to the Coulombic formula, so there are 2 or 3 sets of A,B,C coefficients
 depending on which pair_style is used.  The boundary conditions
 applied to the smoothing function are as follows: S(r1) = S'(r1) = 0,
-S(rc) = -F(rc), S'(rc) = -F'(rc), where F(r) is the correpsonding term
-in the LJ or Coulombic function and a single quote represents a
-derivative with respect to r.
+S(rc) = -F(rc), S'(rc) = -F'(rc), where F(r) is the corresponding term
+in the LJ or Coulombic potential energy function and a 
+single quote represents a derivative with respect to r.
 
 The inner and outer cutoff for the LJ and Coulombic terms can be the
 same or different depending on whether 2 or 4 arguments are used in