diff --git a/src/USER-FEP/pair_lj_charmm_coul_long_soft.cpp b/src/USER-FEP/pair_lj_charmm_coul_long_soft.cpp
new file mode 100644
index 0000000000..3ba892c1e1
--- /dev/null
+++ b/src/USER-FEP/pair_lj_charmm_coul_long_soft.cpp
@@ -0,0 +1,1024 @@
+/* ----------------------------------------------------------------------
+   LAMMPS - Large-scale Atomic/Molecular Massively Parallel Simulator
+   http://lammps.sandia.gov, Sandia National Laboratories
+   Steve Plimpton, sjplimp@sandia.gov
+
+   Copyright (2003) Sandia Corporation.  Under the terms of Contract
+   DE-AC04-94AL85000 with Sandia Corporation, the U.S. Government retains
+   certain rights in this software.  This software is distributed under
+   the GNU General Public License.
+
+   See the README file in the top-level LAMMPS directory.
+------------------------------------------------------------------------- */
+
+/* ----------------------------------------------------------------------
+   Contributing author: Paul Crozier (SNL)
+   Soft-core version: Agilio Padua (Univ Blaise Pascal & CNRS)
+------------------------------------------------------------------------- */
+
+#include "math.h"
+#include "stdio.h"
+#include "stdlib.h"
+#include "string.h"
+#include "pair_lj_charmm_coul_long_soft.h"
+#include "atom.h"
+#include "comm.h"
+#include "force.h"
+#include "kspace.h"
+#include "update.h"
+#include "integrate.h"
+#include "respa.h"
+#include "neighbor.h"
+#include "neigh_list.h"
+#include "neigh_request.h"
+#include "memory.h"
+#include "error.h"
+
+using namespace LAMMPS_NS;
+
+#define EWALD_F   1.12837917
+#define EWALD_P   0.3275911
+#define A1        0.254829592
+#define A2       -0.284496736
+#define A3        1.421413741
+#define A4       -1.453152027
+#define A5        1.061405429
+
+/* ---------------------------------------------------------------------- */
+
+PairLJCharmmCoulLongSoft::PairLJCharmmCoulLongSoft(LAMMPS *lmp) : Pair(lmp)
+{
+  respa_enable = 1;
+  ewaldflag = pppmflag = 1;
+  implicit = 0;
+  mix_flag = ARITHMETIC;
+  writedata = 1;
+}
+
+/* ---------------------------------------------------------------------- */
+
+PairLJCharmmCoulLongSoft::~PairLJCharmmCoulLongSoft()
+{
+  if (allocated) {
+    memory->destroy(setflag);
+    memory->destroy(cutsq);
+
+    memory->destroy(epsilon);
+    memory->destroy(sigma);
+    memory->destroy(lambda);
+    memory->destroy(eps14);
+    memory->destroy(sigma14);
+    memory->destroy(lj1);
+    memory->destroy(lj2);
+    memory->destroy(lj3);
+    memory->destroy(lj4);
+    memory->destroy(lj14_1);
+    memory->destroy(lj14_2);
+    memory->destroy(lj14_3);
+    memory->destroy(lj14_4);
+  }
+}
+
+/* ---------------------------------------------------------------------- */
+
+void PairLJCharmmCoulLongSoft::compute(int eflag, int vflag)
+{
+  int i,j,ii,jj,inum,jnum,itype,jtype;
+  double qtmp,xtmp,ytmp,ztmp,delx,dely,delz,evdwl,ecoul,fpair;
+  double r,rsq,forcecoul,forcelj,factor_coul,factor_lj;
+  double grij,expm2,prefactor,t,erfc;
+  double philj,switch1,switch2;
+  double denc, denlj, r4sig6;
+  int *ilist,*jlist,*numneigh,**firstneigh;
+
+  evdwl = ecoul = 0.0;
+  if (eflag || vflag) ev_setup(eflag,vflag);
+  else evflag = vflag_fdotr = 0;
+
+  double **x = atom->x;
+  double **f = atom->f;
+  double *q = atom->q;
+  int *type = atom->type;
+  int nlocal = atom->nlocal;
+  double *special_coul = force->special_coul;
+  double *special_lj = force->special_lj;
+  int newton_pair = force->newton_pair;
+  double qqrd2e = force->qqrd2e;
+
+  inum = list->inum;
+  ilist = list->ilist;
+  numneigh = list->numneigh;
+  firstneigh = list->firstneigh;
+
+  // loop over neighbors of my atoms
+
+  for (ii = 0; ii < inum; ii++) {
+    i = ilist[ii];
+    qtmp = q[i];
+    xtmp = x[i][0];
+    ytmp = x[i][1];
+    ztmp = x[i][2];
+    itype = type[i];
+    jlist = firstneigh[i];
+    jnum = numneigh[i];
+
+    for (jj = 0; jj < jnum; jj++) {
+      j = jlist[jj];
+      factor_lj = special_lj[sbmask(j)];
+      factor_coul = special_coul[sbmask(j)];
+      j &= NEIGHMASK;
+
+      delx = xtmp - x[j][0];
+      dely = ytmp - x[j][1];
+      delz = ztmp - x[j][2];
+      rsq = delx*delx + dely*dely + delz*delz;
+      jtype = type[j];
+
+      if (rsq < cut_bothsq) {
+
+        if (rsq < cut_coulsq) {
+          r = sqrt(rsq);
+          grij = g_ewald * r;
+          expm2 = exp(-grij*grij);
+          t = 1.0 / (1.0 + EWALD_P*grij);
+          erfc = t * (A1+t*(A2+t*(A3+t*(A4+t*A5)))) * expm2;
+
+          denc = sqrt(lj4[itype][jtype] + rsq);
+          prefactor = qqrd2e * lj1[itype][jtype] * qtmp*q[j] / (denc*denc*denc);
+
+          forcecoul = prefactor * (erfc + EWALD_F*grij*expm2);
+          if (factor_coul < 1.0) forcecoul -= (1.0-factor_coul)*prefactor;
+        } else forcecoul = 0.0;
+
+        if (rsq < cut_ljsq) {
+          r4sig6 = rsq*rsq / lj2[itype][jtype];
+          denlj = lj3[itype][jtype] + rsq*r4sig6;
+          forcelj = lj1[itype][jtype] * epsilon[itype][jtype] * 
+            (48.0*r4sig6/(denlj*denlj*denlj) - 24.0*r4sig6/(denlj*denlj));
+
+          if (rsq > cut_lj_innersq) {
+            switch1 = (cut_ljsq-rsq) * (cut_ljsq-rsq) *
+              (cut_ljsq + 2.0*rsq - 3.0*cut_lj_innersq) / denom_lj;
+            switch2 = 12.0 * (cut_ljsq-rsq) * (rsq-cut_lj_innersq) / denom_lj;
+            philj = lj1[itype][jtype] * 4.0 * epsilon[itype][jtype] * 
+              (1.0/(denlj*denlj) - 1.0/denlj);
+            forcelj = forcelj*switch1 + philj*switch2;
+          }
+        } else forcelj = 0.0;
+
+        fpair = forcecoul + factor_lj*forcelj;
+
+        f[i][0] += delx*fpair;
+        f[i][1] += dely*fpair;
+        f[i][2] += delz*fpair;
+        if (newton_pair || j < nlocal) {
+          f[j][0] -= delx*fpair;
+          f[j][1] -= dely*fpair;
+          f[j][2] -= delz*fpair;
+        }
+
+        if (eflag) {
+          if (rsq < cut_coulsq) {
+            prefactor = qqrd2e * lj1[itype][jtype] * qtmp*q[j] / denc;
+            ecoul = prefactor*erfc;
+            if (factor_coul < 1.0) ecoul -= (1.0-factor_coul)*prefactor;
+          } else ecoul = 0.0;
+
+          if (rsq < cut_ljsq) {
+            evdwl = lj1[itype][jtype] * 4.0 * epsilon[itype][jtype] * 
+              (1.0/(denlj*denlj) - 1.0/denlj);
+            if (rsq > cut_lj_innersq) {
+              switch1 = (cut_ljsq-rsq) * (cut_ljsq-rsq) *
+                (cut_ljsq + 2.0*rsq - 3.0*cut_lj_innersq) / denom_lj;
+              evdwl *= switch1;
+            }
+            evdwl *= factor_lj;
+          } else evdwl = 0.0;
+        }
+
+        if (evflag) ev_tally(i,j,nlocal,newton_pair,
+                             evdwl,ecoul,fpair,delx,dely,delz);
+      }
+    }
+  }
+
+  if (vflag_fdotr) virial_fdotr_compute();
+}
+
+/* ---------------------------------------------------------------------- */
+
+void PairLJCharmmCoulLongSoft::compute_inner()
+{
+  int i,j,ii,jj,inum,jnum,itype,jtype;
+  double qtmp,xtmp,ytmp,ztmp,delx,dely,delz,fpair;
+  double rsq,forcecoul,forcelj,factor_coul,factor_lj;
+  double rsw;
+  double denc, denlj, r4sig6;
+  int *ilist,*jlist,*numneigh,**firstneigh;
+
+  double **x = atom->x;
+  double **f = atom->f;
+  double *q = atom->q;
+  int *type = atom->type;
+  int nlocal = atom->nlocal;
+  double *special_coul = force->special_coul;
+  double *special_lj = force->special_lj;
+  int newton_pair = force->newton_pair;
+  double qqrd2e = force->qqrd2e;
+
+  inum = listinner->inum;
+  ilist = listinner->ilist;
+  numneigh = listinner->numneigh;
+  firstneigh = listinner->firstneigh;
+
+  double cut_out_on = cut_respa[0];
+  double cut_out_off = cut_respa[1];
+
+  double cut_out_diff = cut_out_off - cut_out_on;
+  double cut_out_on_sq = cut_out_on*cut_out_on;
+  double cut_out_off_sq = cut_out_off*cut_out_off;
+
+  // loop over neighbors of my atoms
+
+  for (ii = 0; ii < inum; ii++) {
+    i = ilist[ii];
+    qtmp = q[i];
+    xtmp = x[i][0];
+    ytmp = x[i][1];
+    ztmp = x[i][2];
+    itype = type[i];
+    jlist = firstneigh[i];
+    jnum = numneigh[i];
+
+    for (jj = 0; jj < jnum; jj++) {
+      j = jlist[jj];
+      factor_lj = special_lj[sbmask(j)];
+      factor_coul = special_coul[sbmask(j)];
+      j &= NEIGHMASK;
+
+      delx = xtmp - x[j][0];
+      dely = ytmp - x[j][1];
+      delz = ztmp - x[j][2];
+      rsq = delx*delx + dely*dely + delz*delz;
+
+      if (rsq < cut_out_off_sq) {
+        jtype = type[j];
+
+        denc = sqrt(lj4[itype][jtype] + rsq);
+        forcecoul = qqrd2e * lj1[itype][jtype] * qtmp*q[j] / (denc*denc*denc);
+        if (factor_coul < 1.0) forcecoul -= (1.0-factor_coul)*forcecoul;
+
+        r4sig6 = rsq*rsq / lj2[itype][jtype];
+        denlj = lj3[itype][jtype] + rsq*r4sig6;
+        forcelj = lj1[itype][jtype] * epsilon[itype][jtype] * 
+          (48.0*r4sig6/(denlj*denlj*denlj) - 24.0*r4sig6/(denlj*denlj));
+
+        fpair = forcecoul + factor_lj*forcelj;
+
+        if (rsq > cut_out_on_sq) {
+          rsw = (sqrt(rsq) - cut_out_on)/cut_out_diff;
+          fpair *= 1.0 + rsw*rsw*(2.0*rsw-3.0);
+        }
+
+        f[i][0] += delx*fpair;
+        f[i][1] += dely*fpair;
+        f[i][2] += delz*fpair;
+        if (newton_pair || j < nlocal) {
+          f[j][0] -= delx*fpair;
+          f[j][1] -= dely*fpair;
+          f[j][2] -= delz*fpair;
+        }
+      }
+    }
+  }
+}
+
+/* ---------------------------------------------------------------------- */
+
+void PairLJCharmmCoulLongSoft::compute_middle()
+{
+  int i,j,ii,jj,inum,jnum,itype,jtype;
+  double qtmp,xtmp,ytmp,ztmp,delx,dely,delz,fpair;
+  double rsq,forcecoul,forcelj,factor_coul,factor_lj;
+  double philj,switch1,switch2;
+  double rsw;
+  double denc, denlj, r4sig6;
+  int *ilist,*jlist,*numneigh,**firstneigh;
+
+  double **x = atom->x;
+  double **f = atom->f;
+  double *q = atom->q;
+  int *type = atom->type;
+  int nlocal = atom->nlocal;
+  double *special_coul = force->special_coul;
+  double *special_lj = force->special_lj;
+  int newton_pair = force->newton_pair;
+  double qqrd2e = force->qqrd2e;
+
+  inum = listmiddle->inum;
+  ilist = listmiddle->ilist;
+  numneigh = listmiddle->numneigh;
+  firstneigh = listmiddle->firstneigh;
+
+  double cut_in_off = cut_respa[0];
+  double cut_in_on = cut_respa[1];
+  double cut_out_on = cut_respa[2];
+  double cut_out_off = cut_respa[3];
+
+  double cut_in_diff = cut_in_on - cut_in_off;
+  double cut_out_diff = cut_out_off - cut_out_on;
+  double cut_in_off_sq = cut_in_off*cut_in_off;
+  double cut_in_on_sq = cut_in_on*cut_in_on;
+  double cut_out_on_sq = cut_out_on*cut_out_on;
+  double cut_out_off_sq = cut_out_off*cut_out_off;
+
+  // loop over neighbors of my atoms
+
+  for (ii = 0; ii < inum; ii++) {
+    i = ilist[ii];
+    qtmp = q[i];
+    xtmp = x[i][0];
+    ytmp = x[i][1];
+    ztmp = x[i][2];
+    itype = type[i];
+
+    jlist = firstneigh[i];
+    jnum = numneigh[i];
+
+    for (jj = 0; jj < jnum; jj++) {
+      j = jlist[jj];
+      factor_lj = special_lj[sbmask(j)];
+      factor_coul = special_coul[sbmask(j)];
+      j &= NEIGHMASK;
+
+      delx = xtmp - x[j][0];
+      dely = ytmp - x[j][1];
+      delz = ztmp - x[j][2];
+      rsq = delx*delx + dely*dely + delz*delz;
+
+      if (rsq < cut_out_off_sq && rsq > cut_in_off_sq) {
+        jtype = type[j];
+
+        denc = sqrt(lj4[itype][jtype] + rsq);
+        forcecoul = qqrd2e * lj1[itype][jtype] * qtmp*q[j] / (denc*denc*denc);
+        if (factor_coul < 1.0) forcecoul -= (1.0-factor_coul)*forcecoul;
+
+        r4sig6 = rsq*rsq / lj2[itype][jtype];
+        denlj = lj3[itype][jtype] + rsq*r4sig6;
+        forcelj = lj1[itype][jtype] * epsilon[itype][jtype] * 
+          (48.0*r4sig6/(denlj*denlj*denlj) - 24.0*r4sig6/(denlj*denlj));
+
+        if (rsq > cut_lj_innersq) {
+          switch1 = (cut_ljsq-rsq) * (cut_ljsq-rsq) *
+            (cut_ljsq + 2.0*rsq - 3.0*cut_lj_innersq) / denom_lj;
+          switch2 = 12.0 * (cut_ljsq-rsq) * (rsq-cut_lj_innersq) / denom_lj;
+          philj = lj1[itype][jtype] * 4.0 * epsilon[itype][jtype] * 
+              (1.0/(denlj*denlj) - 1.0/denlj);
+          forcelj = forcelj*switch1 + philj*switch2;
+        }
+
+        fpair = forcecoul + factor_lj*forcelj;
+
+        if (rsq < cut_in_on_sq) {
+          rsw = (sqrt(rsq) - cut_in_off)/cut_in_diff;
+          fpair *= rsw*rsw*(3.0 - 2.0*rsw);
+        }
+        if (rsq > cut_out_on_sq) {
+          rsw = (sqrt(rsq) - cut_out_on)/cut_out_diff;
+          fpair *= 1.0 + rsw*rsw*(2.0*rsw - 3.0);
+        }
+
+        f[i][0] += delx*fpair;
+        f[i][1] += dely*fpair;
+        f[i][2] += delz*fpair;
+        if (newton_pair || j < nlocal) {
+          f[j][0] -= delx*fpair;
+          f[j][1] -= dely*fpair;
+          f[j][2] -= delz*fpair;
+        }
+      }
+    }
+  }
+}
+
+/* ---------------------------------------------------------------------- */
+
+void PairLJCharmmCoulLongSoft::compute_outer(int eflag, int vflag)
+{
+  int i,j,ii,jj,inum,jnum,itype,jtype;
+  double qtmp,xtmp,ytmp,ztmp,delx,dely,delz,evdwl,ecoul,fpair;
+  double r,rsq,forcecoul,forcelj,factor_coul,factor_lj;
+  double grij,expm2,fprefactor,eprefactor,t,erfc;
+  double philj,switch1,switch2;
+  double rsw;
+  double denc, denlj, r4sig6;
+  int *ilist,*jlist,*numneigh,**firstneigh;
+
+  evdwl = ecoul = 0.0;
+  if (eflag || vflag) ev_setup(eflag,vflag);
+  else evflag = 0;
+
+  double **x = atom->x;
+  double **f = atom->f;
+  double *q = atom->q;
+  int *type = atom->type;
+  int nlocal = atom->nlocal;
+  double *special_coul = force->special_coul;
+  double *special_lj = force->special_lj;
+  int newton_pair = force->newton_pair;
+  double qqrd2e = force->qqrd2e;
+
+  inum = listouter->inum;
+  ilist = listouter->ilist;
+  numneigh = listouter->numneigh;
+  firstneigh = listouter->firstneigh;
+
+  double cut_in_off = cut_respa[2];
+  double cut_in_on = cut_respa[3];
+
+  double cut_in_diff = cut_in_on - cut_in_off;
+  double cut_in_off_sq = cut_in_off*cut_in_off;
+  double cut_in_on_sq = cut_in_on*cut_in_on;
+
+  // loop over neighbors of my atoms
+
+  for (ii = 0; ii < inum; ii++) {
+    i = ilist[ii];
+    qtmp = q[i];
+    xtmp = x[i][0];
+    ytmp = x[i][1];
+    ztmp = x[i][2];
+    itype = type[i];
+    jlist = firstneigh[i];
+    jnum = numneigh[i];
+
+    for (jj = 0; jj < jnum; jj++) {
+      j = jlist[jj];
+      factor_lj = special_lj[sbmask(j)];
+      factor_coul = special_coul[sbmask(j)];
+      j &= NEIGHMASK;
+
+      delx = xtmp - x[j][0];
+      dely = ytmp - x[j][1];
+      delz = ztmp - x[j][2];
+      rsq = delx*delx + dely*dely + delz*delz;
+
+      if (rsq < cut_bothsq) {
+        jtype = type[j];
+
+        if (rsq < cut_coulsq) {
+          r = sqrt(rsq);
+          grij = g_ewald * r;
+          expm2 = exp(-grij*grij);
+          t = 1.0 / (1.0 + EWALD_P*grij);
+          erfc = t * (A1+t*(A2+t*(A3+t*(A4+t*A5)))) * expm2;
+
+          denc = sqrt(lj4[itype][jtype] + rsq);
+          fprefactor = qqrd2e * lj1[itype][jtype] * qtmp*q[j] /
+            (denc*denc*denc);
+
+          forcecoul = fprefactor * (erfc + EWALD_F*grij*expm2 - 1.0);
+
+          if (rsq > cut_in_off_sq) {
+            if (rsq < cut_in_on_sq) {
+              rsw = (r - cut_in_off)/cut_in_diff;
+              forcecoul += fprefactor*rsw*rsw*(3.0 - 2.0*rsw);
+              if (factor_coul < 1.0)
+                forcecoul -=
+                  (1.0-factor_coul)*fprefactor*rsw*rsw*(3.0 - 2.0*rsw);
+            } else {
+              forcecoul += fprefactor;
+              if (factor_coul < 1.0)
+                forcecoul -= (1.0-factor_coul)*fprefactor;
+            }
+          }
+        } else forcecoul = 0.0;
+
+        if (rsq < cut_ljsq && rsq > cut_in_off_sq) {
+          r4sig6 = rsq*rsq / lj2[itype][jtype];
+          denlj = lj3[itype][jtype] + rsq*r4sig6;
+          forcelj = lj1[itype][jtype] * epsilon[itype][jtype] * 
+            (48.0*r4sig6/(denlj*denlj*denlj) - 24.0*r4sig6/(denlj*denlj));
+
+          if (rsq > cut_lj_innersq) {
+            switch1 = (cut_ljsq-rsq) * (cut_ljsq-rsq) *
+              (cut_ljsq + 2.0*rsq - 3.0*cut_lj_innersq) / denom_lj;
+            switch2 = 12.0 * (cut_ljsq-rsq) * (rsq-cut_lj_innersq) / denom_lj;
+            philj = lj1[itype][jtype] * 4.0 * epsilon[itype][jtype] * 
+              (1.0/(denlj*denlj) - 1.0/denlj);
+            forcelj = forcelj*switch1 + philj*switch2;
+          }
+          if (rsq < cut_in_on_sq) {
+            rsw = (sqrt(rsq) - cut_in_off)/cut_in_diff;
+            forcelj *= rsw*rsw*(3.0 - 2.0*rsw);
+          }
+        } else forcelj = 0.0;
+
+        fpair = forcecoul + forcelj;
+
+        f[i][0] += delx*fpair;
+        f[i][1] += dely*fpair;
+        f[i][2] += delz*fpair;
+        if (newton_pair || j < nlocal) {
+          f[j][0] -= delx*fpair;
+          f[j][1] -= dely*fpair;
+          f[j][2] -= delz*fpair;
+        }
+
+        if (eflag) {
+          if (rsq < cut_coulsq) {
+            eprefactor = qqrd2e * lj1[itype][jtype] * qtmp*q[j] / denc;
+            ecoul = eprefactor*erfc;
+            if (factor_coul < 1.0) ecoul -= (1.0-factor_coul)*eprefactor;
+          } else ecoul = 0.0;
+
+          if (rsq < cut_ljsq) {
+            evdwl = lj1[itype][jtype] * 4.0 * epsilon[itype][jtype] * 
+              (1.0/(denlj*denlj) - 1.0/denlj);
+            if (rsq > cut_lj_innersq) {
+              switch1 = (cut_ljsq-rsq) * (cut_ljsq-rsq) *
+                (cut_ljsq + 2.0*rsq - 3.0*cut_lj_innersq) / denom_lj;
+              evdwl *= switch1;
+            }
+            evdwl *= factor_lj;
+          } else evdwl = 0.0;
+        }
+
+        if (vflag) {
+          if (rsq < cut_coulsq) {
+            forcecoul = fprefactor * (erfc + EWALD_F*grij*expm2);
+            if (factor_coul < 1.0) forcecoul -= (1.0-factor_coul)*fprefactor;
+          } else forcecoul = 0.0;
+
+          if (rsq <= cut_in_off_sq) {
+            r4sig6 = rsq*rsq / lj2[itype][jtype];
+            denlj = lj3[itype][jtype] + rsq*r4sig6;
+            forcelj = lj1[itype][jtype] * epsilon[itype][jtype] * 
+              (48.0*r4sig6/(denlj*denlj*denlj) - 24.0*r4sig6/(denlj*denlj));
+
+            if (rsq > cut_lj_innersq) {
+              switch1 = (cut_ljsq-rsq) * (cut_ljsq-rsq) *
+                (cut_ljsq + 2.0*rsq - 3.0*cut_lj_innersq) / denom_lj;
+              switch2 = 12.0 * (cut_ljsq-rsq) * (rsq-cut_lj_innersq) / denom_lj;
+              philj = lj1[itype][jtype] * 4.0 * epsilon[itype][jtype] * 
+                (1.0/(denlj*denlj) - 1.0/denlj);
+              forcelj = forcelj*switch1 + philj*switch2;
+            }
+          } else if (rsq <= cut_in_on_sq) {
+            forcelj = lj1[itype][jtype] * epsilon[itype][jtype] * 
+              (48.0*r4sig6/(denlj*denlj*denlj) - 24.0*r4sig6/(denlj*denlj));
+            if (rsq > cut_lj_innersq) {
+              switch1 = (cut_ljsq-rsq) * (cut_ljsq-rsq) *
+                (cut_ljsq + 2.0*rsq - 3.0*cut_lj_innersq) / denom_lj;
+              switch2 = 12.0 * (cut_ljsq-rsq) * (rsq-cut_lj_innersq) / denom_lj;
+              philj = lj1[itype][jtype] * 4.0 * epsilon[itype][jtype] * 
+                (1.0/(denlj*denlj) - 1.0/denlj);
+              forcelj = forcelj*switch1 + philj*switch2;
+            }
+          }
+          fpair = forcecoul + factor_lj*forcelj;
+        }
+
+        if (evflag) ev_tally(i,j,nlocal,newton_pair,
+                             evdwl,ecoul,fpair,delx,dely,delz);
+      }
+    }
+  }
+}
+
+/* ----------------------------------------------------------------------
+   allocate all arrays
+------------------------------------------------------------------------- */
+
+void PairLJCharmmCoulLongSoft::allocate()
+{
+  allocated = 1;
+  int n = atom->ntypes;
+
+  memory->create(setflag,n+1,n+1,"pair:setflag");
+  for (int i = 1; i <= n; i++)
+    for (int j = i; j <= n; j++)
+      setflag[i][j] = 0;
+
+  memory->create(cutsq,n+1,n+1,"pair:cutsq");
+
+  memory->create(epsilon,n+1,n+1,"pair:epsilon");
+  memory->create(sigma,n+1,n+1,"pair:sigma");
+  memory->create(lambda,n+1,n+1,"pair:lambda");
+  memory->create(eps14,n+1,n+1,"pair:eps14");
+  memory->create(sigma14,n+1,n+1,"pair:sigma14");
+  memory->create(lj1,n+1,n+1,"pair:lj1");
+  memory->create(lj2,n+1,n+1,"pair:lj2");
+  memory->create(lj3,n+1,n+1,"pair:lj3");
+  memory->create(lj4,n+1,n+1,"pair:lj4");
+  memory->create(lj14_1,n+1,n+1,"pair:lj14_1");
+  memory->create(lj14_2,n+1,n+1,"pair:lj14_2");
+  memory->create(lj14_3,n+1,n+1,"pair:lj14_3");
+  memory->create(lj14_4,n+1,n+1,"pair:lj14_4");
+}
+
+/* ----------------------------------------------------------------------
+   global settings
+   unlike other pair styles,
+     there are no individual pair settings that these override
+------------------------------------------------------------------------- */
+
+void PairLJCharmmCoulLongSoft::settings(int narg, char **arg)
+{
+  if (narg != 5 && narg != 6) error->all(FLERR,"Illegal pair_style command");
+
+  nlambda = force->numeric(FLERR,arg[0]);
+  alphalj = force->numeric(FLERR,arg[1]);
+  alphac  = force->numeric(FLERR,arg[2]);
+
+  cut_lj_inner = force->numeric(FLERR,arg[3]);
+  cut_lj = force->numeric(FLERR,arg[4]);
+  if (narg == 5) cut_coul = cut_lj;
+  else cut_coul = force->numeric(FLERR,arg[5]);
+}
+
+/* ----------------------------------------------------------------------
+   set coeffs for one or more type pairs
+------------------------------------------------------------------------- */
+
+void PairLJCharmmCoulLongSoft::coeff(int narg, char **arg)
+{
+  if (narg != 5 && narg != 7) error->all(FLERR,"Illegal pair_coeff command");
+  if (!allocated) allocate();
+
+  int ilo,ihi,jlo,jhi;
+  force->bounds(arg[0],atom->ntypes,ilo,ihi);
+  force->bounds(arg[1],atom->ntypes,jlo,jhi);
+
+  double epsilon_one = force->numeric(FLERR,arg[2]);
+  double sigma_one = force->numeric(FLERR,arg[3]);
+  double lambda_one = force->numeric(FLERR,arg[4]);
+
+  double eps14_one = epsilon_one;
+  double sigma14_one = sigma_one;
+  if (narg == 7) {
+    eps14_one = force->numeric(FLERR,arg[5]);
+    sigma14_one = force->numeric(FLERR,arg[6]);
+  }
+
+  int count = 0;
+  for (int i = ilo; i <= ihi; i++) {
+    for (int j = MAX(jlo,i); j <= jhi; j++) {
+      epsilon[i][j] = epsilon_one;
+      sigma[i][j] = sigma_one;
+      lambda[i][j] = lambda_one;
+      eps14[i][j] = eps14_one;
+      sigma14[i][j] = sigma14_one;
+      setflag[i][j] = 1;
+      count++;
+    }
+  }
+
+  if (count == 0) error->all(FLERR,"Incorrect args for pair coefficients");
+}
+
+/* ----------------------------------------------------------------------
+   init specific to this pair style
+------------------------------------------------------------------------- */
+
+void PairLJCharmmCoulLongSoft::init_style()
+{
+  if (!atom->q_flag)
+    error->all(FLERR,
+               "Pair style lj/charmm/coul/long/soft requires atom attribute q");
+
+  // request regular or rRESPA neighbor lists
+
+  int irequest;
+
+  if (update->whichflag == 1 && strstr(update->integrate_style,"respa")) {
+    int respa = 0;
+    if (((Respa *) update->integrate)->level_inner >= 0) respa = 1;
+    if (((Respa *) update->integrate)->level_middle >= 0) respa = 2;
+
+    if (respa == 0) irequest = neighbor->request(this);
+    else if (respa == 1) {
+      irequest = neighbor->request(this);
+      neighbor->requests[irequest]->id = 1;
+      neighbor->requests[irequest]->half = 0;
+      neighbor->requests[irequest]->respainner = 1;
+      irequest = neighbor->request(this);
+      neighbor->requests[irequest]->id = 3;
+      neighbor->requests[irequest]->half = 0;
+      neighbor->requests[irequest]->respaouter = 1;
+    } else {
+      irequest = neighbor->request(this);
+      neighbor->requests[irequest]->id = 1;
+      neighbor->requests[irequest]->half = 0;
+      neighbor->requests[irequest]->respainner = 1;
+      irequest = neighbor->request(this);
+      neighbor->requests[irequest]->id = 2;
+      neighbor->requests[irequest]->half = 0;
+      neighbor->requests[irequest]->respamiddle = 1;
+      irequest = neighbor->request(this);
+      neighbor->requests[irequest]->id = 3;
+      neighbor->requests[irequest]->half = 0;
+      neighbor->requests[irequest]->respaouter = 1;
+    }
+
+  } else irequest = neighbor->request(this);
+
+  // require cut_lj_inner < cut_lj
+
+  if (cut_lj_inner >= cut_lj)
+    error->all(FLERR,"Pair inner cutoff >= Pair outer cutoff");
+
+  cut_lj_innersq = cut_lj_inner * cut_lj_inner;
+  cut_ljsq = cut_lj * cut_lj;
+  cut_coulsq = cut_coul * cut_coul;
+  cut_bothsq = MAX(cut_ljsq,cut_coulsq);
+
+  denom_lj = (cut_ljsq-cut_lj_innersq) * (cut_ljsq-cut_lj_innersq) *
+    (cut_ljsq-cut_lj_innersq);
+
+  // set & error check interior rRESPA cutoffs
+
+  if (strstr(update->integrate_style,"respa") &&
+      ((Respa *) update->integrate)->level_inner >= 0) {
+    cut_respa = ((Respa *) update->integrate)->cutoff;
+    if (MIN(cut_lj,cut_coul) < cut_respa[3])
+      error->all(FLERR,"Pair cutoff < Respa interior cutoff");
+    if (cut_lj_inner < cut_respa[1])
+      error->all(FLERR,"Pair inner cutoff < Respa interior cutoff");
+  } else cut_respa = NULL;
+
+  // insure use of KSpace long-range solver, set g_ewald
+
+  if (force->kspace == NULL)
+    error->all(FLERR,"Pair style requires a KSpace style");
+  g_ewald = force->kspace->g_ewald;
+}
+
+/* ----------------------------------------------------------------------
+   neighbor callback to inform pair style of neighbor list to use
+   regular or rRESPA
+------------------------------------------------------------------------- */
+
+void PairLJCharmmCoulLongSoft::init_list(int id, NeighList *ptr)
+{
+  if (id == 0) list = ptr;
+  else if (id == 1) listinner = ptr;
+  else if (id == 2) listmiddle = ptr;
+  else if (id == 3) listouter = ptr;
+}
+
+/* ----------------------------------------------------------------------
+   init for one type pair i,j and corresponding j,i
+------------------------------------------------------------------------- */
+
+double PairLJCharmmCoulLongSoft::init_one(int i, int j)
+{
+  if (setflag[i][j] == 0) {
+    epsilon[i][j] = mix_energy(epsilon[i][i],epsilon[j][j],
+                               sigma[i][i],sigma[j][j]);
+    sigma[i][j] = mix_distance(sigma[i][i],sigma[j][j]);
+    if (lambda[i][i] != lambda[j][j])
+      error->all(FLERR,"Pair lj/charmm/coul/long/soft different lambda values in mix");
+    lambda[i][j] = lambda[i][i];
+    eps14[i][j] = mix_energy(eps14[i][i],eps14[j][j],
+                               sigma14[i][i],sigma14[j][j]);
+    sigma14[i][j] = mix_distance(sigma14[i][i],sigma14[j][j]);
+  }
+
+  double cut = MAX(cut_lj,cut_coul);
+
+  lj1[i][j] = pow(lambda[i][j], nlambda);
+  lj2[i][j] = pow(sigma[i][j], 6.0);
+  lj3[i][j] = alphalj * (1.0 - lambda[i][j])*(1.0 - lambda[i][j]);
+  lj4[i][j] = alphac  * (1.0 - lambda[i][j])*(1.0 - lambda[i][j]);
+
+  // 1-4 interactions unaffected (they're part of the dihedral term)
+  lj14_1[i][j] = 48.0 * eps14[i][j] * pow(sigma14[i][j],12.0);
+  lj14_2[i][j] = 24.0 * eps14[i][j] * pow(sigma14[i][j],6.0);
+  lj14_3[i][j] = 4.0 * eps14[i][j] * pow(sigma14[i][j],12.0);
+  lj14_4[i][j] = 4.0 * eps14[i][j] * pow(sigma14[i][j],6.0);
+
+  epsilon[j][i] = epsilon[i][j];
+  sigma[j][i] = sigma[i][j];
+  lambda[j][i] = lambda[i][j];
+  lj1[j][i] = lj1[i][j];
+  lj2[j][i] = lj2[i][j];
+  lj3[j][i] = lj3[i][j];
+  lj4[j][i] = lj4[i][j];
+  lj14_1[j][i] = lj14_1[i][j];
+  lj14_2[j][i] = lj14_2[i][j];
+  lj14_3[j][i] = lj14_3[i][j];
+  lj14_4[j][i] = lj14_4[i][j];
+
+  return cut;
+}
+
+/* ----------------------------------------------------------------------
+  proc 0 writes to restart file
+------------------------------------------------------------------------- */
+
+void PairLJCharmmCoulLongSoft::write_restart(FILE *fp)
+{
+  write_restart_settings(fp);
+
+  int i,j;
+  for (i = 1; i <= atom->ntypes; i++)
+    for (j = i; j <= atom->ntypes; j++) {
+      fwrite(&setflag[i][j],sizeof(int),1,fp);
+      if (setflag[i][j]) {
+        fwrite(&epsilon[i][j],sizeof(double),1,fp);
+        fwrite(&sigma[i][j],sizeof(double),1,fp);
+        fwrite(&lambda[i][j],sizeof(double),1,fp);
+        fwrite(&eps14[i][j],sizeof(double),1,fp);
+        fwrite(&sigma14[i][j],sizeof(double),1,fp);
+      }
+    }
+}
+
+/* ----------------------------------------------------------------------
+  proc 0 reads from restart file, bcasts
+------------------------------------------------------------------------- */
+
+void PairLJCharmmCoulLongSoft::read_restart(FILE *fp)
+{
+  read_restart_settings(fp);
+
+  allocate();
+
+  int i,j;
+  int me = comm->me;
+  for (i = 1; i <= atom->ntypes; i++)
+    for (j = i; j <= atom->ntypes; j++) {
+      if (me == 0) fread(&setflag[i][j],sizeof(int),1,fp);
+      MPI_Bcast(&setflag[i][j],1,MPI_INT,0,world);
+      if (setflag[i][j]) {
+        if (me == 0) {
+          fread(&epsilon[i][j],sizeof(double),1,fp);
+          fread(&sigma[i][j],sizeof(double),1,fp);
+          fread(&lambda[i][j],sizeof(double),1,fp);
+          fread(&eps14[i][j],sizeof(double),1,fp);
+          fread(&sigma14[i][j],sizeof(double),1,fp);
+        }
+        MPI_Bcast(&epsilon[i][j],1,MPI_DOUBLE,0,world);
+        MPI_Bcast(&sigma[i][j],1,MPI_DOUBLE,0,world);
+        MPI_Bcast(&lambda[i][j],1,MPI_DOUBLE,0,world);
+        MPI_Bcast(&eps14[i][j],1,MPI_DOUBLE,0,world);
+        MPI_Bcast(&sigma14[i][j],1,MPI_DOUBLE,0,world);
+      }
+    }
+}
+
+/* ----------------------------------------------------------------------
+  proc 0 writes to restart file
+------------------------------------------------------------------------- */
+
+void PairLJCharmmCoulLongSoft::write_restart_settings(FILE *fp)
+{
+  fwrite(&nlambda,sizeof(double),1,fp);
+  fwrite(&alphalj,sizeof(double),1,fp);
+  fwrite(&alphac,sizeof(double),1,fp);
+
+  fwrite(&cut_lj_inner,sizeof(double),1,fp);
+  fwrite(&cut_lj,sizeof(double),1,fp);
+  fwrite(&cut_coul,sizeof(double),1,fp);
+  fwrite(&offset_flag,sizeof(int),1,fp);
+  fwrite(&mix_flag,sizeof(int),1,fp);
+}
+
+/* ----------------------------------------------------------------------
+  proc 0 reads from restart file, bcasts
+------------------------------------------------------------------------- */
+
+void PairLJCharmmCoulLongSoft::read_restart_settings(FILE *fp)
+{
+  if (comm->me == 0) {
+    fread(&nlambda,sizeof(double),1,fp);
+    fread(&alphalj,sizeof(double),1,fp);
+    fread(&alphac,sizeof(double),1,fp);
+
+    fread(&cut_lj_inner,sizeof(double),1,fp);
+    fread(&cut_lj,sizeof(double),1,fp);
+    fread(&cut_coul,sizeof(double),1,fp);
+    fread(&offset_flag,sizeof(int),1,fp);
+    fread(&mix_flag,sizeof(int),1,fp);
+  }
+
+  MPI_Bcast(&nlambda,1,MPI_DOUBLE,0,world);
+  MPI_Bcast(&alphalj,1,MPI_DOUBLE,0,world);
+  MPI_Bcast(&alphac,1,MPI_DOUBLE,0,world);
+
+  MPI_Bcast(&cut_lj_inner,1,MPI_DOUBLE,0,world);
+  MPI_Bcast(&cut_lj,1,MPI_DOUBLE,0,world);
+  MPI_Bcast(&cut_coul,1,MPI_DOUBLE,0,world);
+  MPI_Bcast(&offset_flag,1,MPI_INT,0,world);
+  MPI_Bcast(&mix_flag,1,MPI_INT,0,world);
+}
+
+
+/* ----------------------------------------------------------------------
+   proc 0 writes to data file
+------------------------------------------------------------------------- */
+
+void PairLJCharmmCoulLongSoft::write_data(FILE *fp)
+{
+  for (int i = 1; i <= atom->ntypes; i++)
+    fprintf(fp,"%d %g %g %g %g %g\n",i,epsilon[i][i],sigma[i][i],
+            lambda[i][i],eps14[i][i],sigma14[i][i]);
+}
+
+/* ----------------------------------------------------------------------
+   proc 0 writes all pairs to data file
+------------------------------------------------------------------------- */
+
+void PairLJCharmmCoulLongSoft::write_data_all(FILE *fp)
+{
+  for (int i = 1; i <= atom->ntypes; i++)
+    for (int j = i; j <= atom->ntypes; j++)
+      fprintf(fp,"%d %d %g %g %g %g %g\n",i,j,epsilon[i][j],sigma[i][j],
+              lambda[i][j],eps14[i][j],sigma14[i][j]);
+}
+
+/* ---------------------------------------------------------------------- */
+
+double PairLJCharmmCoulLongSoft::single(int i, int j, int itype, int jtype,
+                                        double rsq,
+                                        double factor_coul, double factor_lj,
+                                        double &fforce)
+{
+  double r,grij,expm2,t,erfc,prefactor;
+  double switch1,switch2,forcecoul,forcelj,phicoul,philj;
+  double denc, denlj, r4sig6;
+
+  if (rsq < cut_coulsq) {
+    r = sqrt(rsq);
+    grij = g_ewald * r;
+    expm2 = exp(-grij*grij);
+    t = 1.0 / (1.0 + EWALD_P*grij);
+    erfc = t * (A1+t*(A2+t*(A3+t*(A4+t*A5)))) * expm2;
+
+    denc = sqrt(lj4[itype][jtype] + rsq);
+    prefactor = force->qqrd2e * lj1[itype][jtype] * atom->q[i]*atom->q[j] /
+      (denc*denc*denc);
+
+    forcecoul = prefactor * (erfc + EWALD_F*grij*expm2);
+    if (factor_coul < 1.0) forcecoul -= (1.0-factor_coul)*prefactor;
+  } else forcecoul = 0.0;
+
+  if (rsq < cut_ljsq) {
+    r4sig6 = rsq*rsq / lj2[itype][jtype];
+    denlj = lj3[itype][jtype] + rsq*r4sig6;
+    forcelj = lj1[itype][jtype] * epsilon[itype][jtype] * 
+      (48.0*r4sig6/(denlj*denlj*denlj) - 24.0*r4sig6/(denlj*denlj));
+    if (rsq > cut_lj_innersq) {
+      switch1 = (cut_ljsq-rsq) * (cut_ljsq-rsq) *
+        (cut_ljsq + 2.0*rsq - 3.0*cut_lj_innersq) / denom_lj;
+      switch2 = 12.0 * (cut_ljsq-rsq) * (rsq-cut_lj_innersq) / denom_lj;
+      philj = lj1[itype][jtype] * 4.0 * epsilon[itype][jtype] * 
+        (1.0/(denlj*denlj) - 1.0/denlj);
+      forcelj = forcelj*switch1 + philj*switch2;
+    }
+  } else forcelj = 0.0;
+  fforce = forcecoul + factor_lj*forcelj;
+
+  double eng = 0.0;
+  if (rsq < cut_coulsq) {
+    prefactor = force->qqrd2e * lj1[itype][jtype] * atom->q[i]*atom->q[j] / denc;
+    phicoul = prefactor*erfc;
+    if (factor_coul < 1.0) phicoul -= (1.0-factor_coul)*prefactor;
+    eng += phicoul;
+  }
+
+  if (rsq < cut_ljsq) {
+    philj = lj1[itype][jtype] * 4.0 * epsilon[itype][jtype] * 
+      (1.0/(denlj*denlj) - 1.0/denlj) - offset[itype][jtype];
+    if (rsq > cut_lj_innersq) {
+      switch1 = (cut_ljsq-rsq) * (cut_ljsq-rsq) *
+        (cut_ljsq + 2.0*rsq - 3.0*cut_lj_innersq) / denom_lj;
+      philj *= switch1;
+    }
+    eng += factor_lj*philj;
+  }
+
+  return eng;
+}
+
+/* ---------------------------------------------------------------------- */
+
+void *PairLJCharmmCoulLongSoft::extract(const char *str, int &dim)
+{
+  dim = 2;
+  if (strcmp(str,"lj14_1") == 0) return (void *) lj14_1;
+  if (strcmp(str,"lj14_2") == 0) return (void *) lj14_2;
+  if (strcmp(str,"lj14_3") == 0) return (void *) lj14_3;
+  if (strcmp(str,"lj14_4") == 0) return (void *) lj14_4;
+
+  if (strcmp(str,"epsilon") == 0) return (void *) epsilon;
+  if (strcmp(str,"sigma") == 0) return (void *) sigma;
+  if (strcmp(str,"lambda") == 0) return (void *) lambda;
+
+  dim = 0;
+  if (strcmp(str,"implicit") == 0) return (void *) &implicit;
+  if (strcmp(str,"cut_coul") == 0) return (void *) &cut_coul;
+
+  return NULL;
+}
diff --git a/src/USER-FEP/pair_lj_charmm_coul_long_soft.h b/src/USER-FEP/pair_lj_charmm_coul_long_soft.h
new file mode 100644
index 0000000000..7e52ec54b5
--- /dev/null
+++ b/src/USER-FEP/pair_lj_charmm_coul_long_soft.h
@@ -0,0 +1,107 @@
+/* -*- c++ -*- ----------------------------------------------------------
+   LAMMPS - Large-scale Atomic/Molecular Massively Parallel Simulator
+   http://lammps.sandia.gov, Sandia National Laboratories
+   Steve Plimpton, sjplimp@sandia.gov
+
+   Copyright (2003) Sandia Corporation.  Under the terms of Contract
+   DE-AC04-94AL85000 with Sandia Corporation, the U.S. Government retains
+   certain rights in this software.  This software is distributed under
+   the GNU General Public License.
+
+   See the README file in the top-level LAMMPS directory.
+------------------------------------------------------------------------- */
+
+#ifdef PAIR_CLASS
+
+PairStyle(lj/charmm/coul/long/soft,PairLJCharmmCoulLongSoft)
+
+#else
+
+#ifndef LMP_PAIR_LJ_CHARMM_COUL_LONG_SOFT_H
+#define LMP_PAIR_LJ_CHARMM_COUL_LONG_SOFT_H
+
+#include "pair.h"
+
+namespace LAMMPS_NS {
+
+class PairLJCharmmCoulLongSoft : public Pair {
+ public:
+  PairLJCharmmCoulLongSoft(class LAMMPS *);
+  virtual ~PairLJCharmmCoulLongSoft();
+
+  virtual void compute(int, int);
+  void settings(int, char **);
+  void coeff(int, char **);
+  void init_style();
+  void init_list(int, class NeighList *);
+  double init_one(int, int);
+  void write_restart(FILE *);
+  void read_restart(FILE *);
+  void write_restart_settings(FILE *);
+  void read_restart_settings(FILE *);
+  void write_data(FILE *);
+  void write_data_all(FILE *);
+  virtual double single(int, int, int, int, double, double, double, double &);
+
+  void compute_inner();
+  void compute_middle();
+  virtual void compute_outer(int, int);
+  virtual void *extract(const char *, int &);
+
+ protected:
+  int implicit;
+  double cut_lj_inner,cut_lj;
+  double cut_lj_innersq,cut_ljsq;
+  double cut_coul,cut_coulsq;
+  double cut_bothsq;
+  double denom_lj;
+  double **epsilon,**sigma,**eps14,**sigma14,**lambda;
+  double nlambda, alphalj, alphac;
+  double **lj1,**lj2,**lj3,**lj4,**offset;
+  double **lj14_1,**lj14_2,**lj14_3,**lj14_4;
+  double *cut_respa;
+  double g_ewald;
+
+  void allocate();
+};
+
+}
+
+#endif
+#endif
+
+/* ERROR/WARNING messages:
+
+E: Illegal ... command
+
+Self-explanatory.  Check the input script syntax and compare to the
+documentation for the command.  You can use -echo screen as a
+command-line option when running LAMMPS to see the offending line.
+
+E: Incorrect args for pair coefficients
+
+Self-explanatory.  Check the input script or data file.
+
+E: Pair style lj/charmm/coul/long/soft requires atom attribute q
+
+The atom style defined does not have these attributes.
+
+E: Pair inner cutoff >= Pair outer cutoff
+
+The specified cutoffs for the pair style are inconsistent.
+
+E: Pair cutoff < Respa interior cutoff
+
+One or more pairwise cutoffs are too short to use with the specified
+rRESPA cutoffs.
+
+E: Pair inner cutoff < Respa interior cutoff
+
+One or more pairwise cutoffs are too short to use with the specified
+rRESPA cutoffs.
+
+E: Pair style requires a KSpace style
+
+No kspace style is defined.
+
+*/