diff -Nru qwwad-1.5.1+15~ubuntu15.10.1/autogen.sh qwwad-1.5.2+15~ubuntu15.10.1/autogen.sh
--- qwwad-1.5.1+15~ubuntu15.10.1/autogen.sh	2016-08-26 08:42:27.000000000 +0000
+++ qwwad-1.5.2+15~ubuntu15.10.1/autogen.sh	2016-09-02 13:30:29.000000000 +0000
@@ -20,6 +20,7 @@
         exit 1
 fi
 
+mkdir -p config
 autoreconf -I m4 -I config --force --install
 
 cd $olddir
diff -Nru qwwad-1.5.1+15~ubuntu15.10.1/configure.ac qwwad-1.5.2+15~ubuntu15.10.1/configure.ac
--- qwwad-1.5.1+15~ubuntu15.10.1/configure.ac	2016-08-26 08:42:27.000000000 +0000
+++ qwwad-1.5.2+15~ubuntu15.10.1/configure.ac	2016-09-02 13:30:29.000000000 +0000
@@ -6,7 +6,7 @@
 dnl List the required versions for dependencies here
 m4_define([libxmlpp_required_version], [2.30])
 
-AC_INIT([Quantum Wells, Wires and Dots], [1.5.1], [https://bugs.launchpad.net/qwwad], [qwwad], [https://launchpad.net/qwwad])
+AC_INIT([Quantum Wells, Wires and Dots], [1.5.2], [https://bugs.launchpad.net/qwwad], [qwwad], [https://launchpad.net/qwwad])
 
 dnl If we have an old version of Autoconf, then we need to set the PACKAGE_URL variable
 dnl manually.
diff -Nru qwwad-1.5.1+15~ubuntu15.10.1/debian/bzr-builder.manifest qwwad-1.5.2+15~ubuntu15.10.1/debian/bzr-builder.manifest
--- qwwad-1.5.1+15~ubuntu15.10.1/debian/bzr-builder.manifest	2016-08-26 08:42:30.000000000 +0000
+++ qwwad-1.5.2+15~ubuntu15.10.1/debian/bzr-builder.manifest	2016-09-02 13:30:32.000000000 +0000
@@ -1,3 +1,3 @@
-# bzr-builder format 0.3 deb-version 1.5.1+15
-lp:qwwad/1.5.x revid:valavanisalex@gmail.com-20160826081519-kgsoq9v597bcql33
+# bzr-builder format 0.3 deb-version 1.5.2+15
+lp:qwwad/1.5.x revid:valavanisalex@gmail.com-20160902131632-68hq2z8sqravrs7f
 nest packaging lp:~qwwad-dev/qwwad/debian debian revid:valavanisalex@gmail.com-20160205102218-36lh2ktmppc6bsre
diff -Nru qwwad-1.5.1+15~ubuntu15.10.1/debian/changelog qwwad-1.5.2+15~ubuntu15.10.1/debian/changelog
--- qwwad-1.5.1+15~ubuntu15.10.1/debian/changelog	2016-08-26 08:42:30.000000000 +0000
+++ qwwad-1.5.2+15~ubuntu15.10.1/debian/changelog	2016-09-02 13:30:32.000000000 +0000
@@ -1,8 +1,8 @@
-qwwad (1.5.1+15~ubuntu15.10.1) wily; urgency=low
+qwwad (1.5.2+15~ubuntu15.10.1) wily; urgency=low
 
   * Auto build.
 
- -- Alex Valavanis <valavanisalex@gmail.com>  Fri, 26 Aug 2016 08:42:30 +0000
+ -- Alex Valavanis <valavanisalex@gmail.com>  Fri, 02 Sep 2016 13:30:32 +0000
 
 qwwad (1.2.0+15) xenial; urgency=low
 
diff -Nru qwwad-1.5.1+15~ubuntu15.10.1/NEWS qwwad-1.5.2+15~ubuntu15.10.1/NEWS
--- qwwad-1.5.1+15~ubuntu15.10.1/NEWS	2016-08-26 08:42:27.000000000 +0000
+++ qwwad-1.5.2+15~ubuntu15.10.1/NEWS	2016-09-02 13:30:29.000000000 +0000
@@ -1,3 +1,8 @@
+2016-09-02 (QWWAD 1.5.2):
+        * Fixed build on 32-bit systems
+        * Improved support for InAlGaAs band structure (bug #1616360).
+          Thanks to Michael Bland-Albrecht for permittivity data.
+
 2016-08-26 (QWWAD 1.5.1):
         * This preview release adds a first version of the libqwwad API, allowing
           you to incorporate QWWAD functionality into your own C++ programs.
diff -Nru qwwad-1.5.1+15~ubuntu15.10.1/src/ppff.cpp qwwad-1.5.2+15~ubuntu15.10.1/src/ppff.cpp
--- qwwad-1.5.1+15~ubuntu15.10.1/src/ppff.cpp	2016-08-26 08:42:27.000000000 +0000
+++ qwwad-1.5.2+15~ubuntu15.10.1/src/ppff.cpp	2016-09-02 13:30:29.000000000 +0000
@@ -447,43 +447,37 @@
 
 }
  
-/* This function reads the atomic species (defined in the file as.r)
-   into memory (addressed by the pointer as) and returns the start
-   address of this block of memory and the number of lines	   */
-atom *read_atoms(long unsigned int *n_atoms, const char * filename)
+/**
+ * \brief Reads the atomic species into memory
+ */
+std::vector<atom> read_atoms(const char * filename)
 {
- int    ia=0;
  FILE 	*Fatoms;        /* file pointer to wavefunction file       */
- atom	*atoms;		/* atomic definitions			*/
 
  if((Fatoms=fopen(filename,"r"))==0)
  {
-  fprintf(stderr,"Error: Cannot open input file 'atoms.xyz'!\n");
-  exit(0);
+     std::ostringstream oss;
+     oss << "Cannot open input file " << filename;
+     throw std::runtime_error(oss.str());
  }
 
  /* Read in the first line and hence the number of atoms	*/
-
- size_t n_read = fscanf(Fatoms,"%lu",n_atoms);
+ int n_atoms=0;
+ size_t n_read = fscanf(Fatoms,"%d", &n_atoms);
  
  /* Allocate memory for atom definitions	*/
- if (n_read == 1)
-   atoms=(atom *)calloc(*n_atoms,sizeof(atom));
- else
- {
-   fprintf(stderr, "Could not read number of atoms!\n");
-   exit(EXIT_FAILURE);
+ std::vector<atom> atoms;
+ if (n_read == 1) {
+   atoms.resize(n_atoms);
  }
-
- if(atoms==0)
- {
-  fprintf(stderr,"Cannot allocate memory!\n");
-  exit(0);
+ else {
+     throw std::runtime_error("Could not read number of atoms");
  }
 
  double rx;
  double ry;
  double rz;
+ int ia=0;
  while((fscanf(Fatoms,"%s %lf %lf %lf",atoms[ia].type,
         &rx,&ry,&rz))!=EOF)
  {
@@ -496,11 +490,11 @@
      r *= 1e-10;
 
      atoms[ia].r = r;
-  ia++;
+     ia++;
  }
  fclose(Fatoms);
 
- return(atoms);
+ return atoms;
 }   
 
 /* This function reads the reciprocal lattice vectors (defined in
diff -Nru qwwad-1.5.1+15~ubuntu15.10.1/src/ppff.h qwwad-1.5.2+15~ubuntu15.10.1/src/ppff.h
--- qwwad-1.5.1+15~ubuntu15.10.1/src/ppff.h	2016-08-26 08:42:27.000000000 +0000
+++ qwwad-1.5.2+15~ubuntu15.10.1/src/ppff.h	2016-09-02 13:30:29.000000000 +0000
@@ -11,6 +11,8 @@
 #define PPFF_H
 
 #include <armadillo>
+#include <vector>
+
 typedef struct
 {
  char	type[12];
@@ -22,7 +24,7 @@
           double        q_sqr,
           const char   *type);
 
-atom * read_atoms(long unsigned int *n_atoms, const char * filename);
+std::vector<atom> read_atoms(const char * filename);
 
 std::vector<arma::vec> read_rlv(double A0);
 #endif
diff -Nru qwwad-1.5.1+15~ubuntu15.10.1/src/pplb-functions.cpp qwwad-1.5.2+15~ubuntu15.10.1/src/pplb-functions.cpp
--- qwwad-1.5.1+15~ubuntu15.10.1/src/pplb-functions.cpp	2016-08-26 08:42:27.000000000 +0000
+++ qwwad-1.5.2+15~ubuntu15.10.1/src/pplb-functions.cpp	2016-09-02 13:30:29.000000000 +0000
@@ -38,27 +38,25 @@
  * \param[in] A0       Lattice constant
  * \param[in] m_per_au conversion factor from SI to a.u.
  * \param[in] atoms    atomic definitions
- * \param[in] n_atoms  number of atoms in structure
  * \param[in] q        a reciprocal lattice vector, G'-G
  */
-std::complex<double> V(double           A0,
-                       double           m_per_au,
-                       atom            *atoms,
-                       size_t           n_atoms,
-                       arma::vec const &q)
+std::complex<double> V(double                   A0,
+                       double                   m_per_au,
+                       std::vector<atom> const &atoms,
+                       arma::vec const         &q)
 {
     std::complex<double> v = 0.0; // potential
     const double q_dot_q = dot(q,q);
 
     // Loop over all atoms in the set and add contribution from each
-    for(unsigned int ia=0; ia<n_atoms; ++ia)
+    for(auto const atom : atoms)
     {
-        const double q_dot_t = dot(q, atoms[ia].r);
-        const double vf = Vf(A0,m_per_au,q_dot_q,atoms[ia].type);
+        const double q_dot_t = dot(q, atom.r);
+        const double vf = Vf(A0,m_per_au,q_dot_q, atom.type);
         v += exp(std::complex<double>(0.0,-q_dot_t)) * vf; // [QWWAD3, 15.76]
     }
 
-    v *= 2.0/n_atoms;
+    v *= 2.0/atoms.size();
 
     return v;
 }
diff -Nru qwwad-1.5.1+15~ubuntu15.10.1/src/pplb-functions.h qwwad-1.5.2+15~ubuntu15.10.1/src/pplb-functions.h
--- qwwad-1.5.1+15~ubuntu15.10.1/src/pplb-functions.h	2016-08-26 08:42:27.000000000 +0000
+++ qwwad-1.5.2+15~ubuntu15.10.1/src/pplb-functions.h	2016-09-02 13:30:29.000000000 +0000
@@ -14,9 +14,8 @@
           int           n_min,
           int           n_max);
 
-std::complex<double> V(double           A0,
-                       double           m_per_au,
-                       atom            *atoms,
-                       size_t           n_atoms,
-                       arma::vec const &q);
+std::complex<double> V(double                   A0,
+                       double                   m_per_au,
+                       std::vector<atom> const &atoms,
+                       arma::vec const         &q);
 #endif
diff -Nru qwwad-1.5.1+15~ubuntu15.10.1/src/qwwad_ef_band_edge.cpp qwwad-1.5.2+15~ubuntu15.10.1/src/qwwad_ef_band_edge.cpp
--- qwwad-1.5.1+15~ubuntu15.10.1/src/qwwad_ef_band_edge.cpp	2016-08-26 08:42:27.000000000 +0000
+++ qwwad-1.5.2+15~ubuntu15.10.1/src/qwwad_ef_band_edge.cpp	2016-09-02 13:30:29.000000000 +0000
@@ -69,6 +69,33 @@
         }
 };
 
+/**
+ * \brief dc relative permittivity values
+ *
+ * \todo Read from material library
+ */
+static double const eps_dc_GaAs = 12.9;
+static double const eps_dc_AlAs = 10.06;
+static double const eps_dc_InAs = 15.15;
+
+/**
+ * \brief Heavy-hole effective masses
+ *
+ * \todo Read from material library
+ */
+static double const m_hh_GaAs = 0.51;
+static double const m_hh_AlAs = 0.76;
+static double const m_hh_InAs = 0.41;
+
+/**
+ * \brief Light-hole effective masses
+ *
+ * \todo Read from material library
+ */
+static double const m_lh_GaAs = 0.082;
+static double const m_lh_AlAs = 0.15;
+static double const m_lh_InAs = 0.026;
+
 int main(int argc,char *argv[])
 {
     const BandEdgeOptions opt(argc, argv);
@@ -146,7 +173,7 @@
                 }
 
                 Eg     = 1.426*e+dV;
-                eps_dc = ((x-1.0)*(-12.9) + x*10.06)*eps0;
+                eps_dc = ((1.0-x)*eps_dc_GaAs + x*eps_dc_AlAs)*eps0;
             }
             break;
 
@@ -233,19 +260,31 @@
                     case 'h':
                         {
                             V=0.47*dV;
-                            if(compute_mass)
-                                std::cerr << "Warning: Mass data not defined for In(1-x-y)Al(x)Ga(y)As light-hole" << std::endl;
+                            if(compute_mass) {
+                                // Linearly interpolate between InAs, AlAs and GaAs for now
+                                // TODO: Find a more accurate interpolation
+                                m = (m_hh_InAs * (1.0-x-y) + m_hh_GaAs * y + m_hh_AlAs * x)*me;
+                            }
                         }
                         break;
                     case 'l':
                         {
-                            std::cerr << "Data not defined for In(1-x-y)Al(x)Ga(y)As light-hole" << std::endl;
-                            exit(EXIT_FAILURE);
+                            std::cerr << "Warning: Potential data not defined for In(1-x-y)Al(x)Ga(y)As light-hole" << std::endl;
+
+                            if(compute_mass) {
+                                // Linearly interpolate between InAs, AlAs and GaAs for now
+                                // TODO: Find a more accurate interpolation
+                                m = (m_lh_InAs * (1.0-x-y) + m_lh_GaAs * y + m_lh_AlAs * x)*me;
+                            }
+
                         }
                 }
 
                 Eg=0.36*e+dV;
-                std::cerr << "Warning: Unknown dc permittivity for InAlGaAs" << std::endl;
+
+                // Linearly interpolate between InAs, AlAs and GaAs for now
+                // TODO: Find a more accurate interpolation
+                eps_dc = (eps_dc_InAs * (1.0-x-y) + eps_dc_GaAs * y + eps_dc_AlAs * x)*eps0;
             }
             break;
     }
diff -Nru qwwad-1.5.1+15~ubuntu15.10.1/src/qwwad_pp_large_basis.cpp qwwad-1.5.2+15~ubuntu15.10.1/src/qwwad_pp_large_basis.cpp
--- qwwad-1.5.1+15~ubuntu15.10.1/src/qwwad_pp_large_basis.cpp	2016-08-26 08:42:27.000000000 +0000
+++ qwwad-1.5.2+15~ubuntu15.10.1/src/qwwad_pp_large_basis.cpp	2016-09-02 13:30:29.000000000 +0000
@@ -90,9 +90,8 @@
         k[ik] *= 2.0*pi/A0;
     }
 
-    size_t	n_atoms;	/* number of atoms in (large) cell		*/
     std::string filename("atoms.xyz");
-    atom *atoms = read_atoms(&n_atoms, filename.c_str());		/* read in atomic basis	*/
+    auto const atoms = read_atoms(filename.c_str());		/* read in atomic basis	*/
 
     const auto G = read_rlv(A0); // read in reciprocal lattice vectors
     const auto N = G.size(); // number of reciprocal lattice vectors
@@ -109,7 +108,7 @@
         for(unsigned int j=i;j<N;j++)
         {
             const auto q = G[i] - G[j];
-            V_GG(i,j) = V(A0,m_per_au,atoms,n_atoms,q);
+            V_GG(i,j) = V(A0,m_per_au,atoms,q);
 
             // Fill in the lower triangle by taking the Hermitian transpose of the elements
             V_GG(j,i) = conj(V_GG(i,j));
@@ -158,8 +157,6 @@
         }
     }/* end while*/
 
-    free(atoms);
-
     return EXIT_SUCCESS;
 }/* end main */
 
diff -Nru qwwad-1.5.1+15~ubuntu15.10.1/src/qwwad_pp_large_basis_so.cpp qwwad-1.5.2+15~ubuntu15.10.1/src/qwwad_pp_large_basis_so.cpp
--- qwwad-1.5.1+15~ubuntu15.10.1/src/qwwad_pp_large_basis_so.cpp	2016-08-26 08:42:27.000000000 +0000
+++ qwwad-1.5.2+15~ubuntu15.10.1/src/qwwad_pp_large_basis_so.cpp	2016-09-02 13:30:29.000000000 +0000
@@ -44,9 +44,8 @@
 using namespace constants;
 
 std::complex<double>
-Vso(const atom                   *atoms,
+Vso(const std::vector<atom>      &atoms,
     const std::vector<arma::vec> &G,
-    const size_t                  n_atoms,
     arma::vec const              &k,
     const unsigned int            i,
     const unsigned int            j,
@@ -95,9 +94,8 @@
         k[ik] *= 2.0*pi/A0;
     }
 
-    size_t	n_atoms;	/* number of atoms in (large) cell		*/
     std::string filename("atoms.xyz");
-    const auto atoms = read_atoms(&n_atoms, filename.c_str()); // read in atomic basis
+    const auto atoms = read_atoms(filename.c_str()); // read in atomic basis
 
     const auto G  = read_rlv(A0); // read in reciprocal lattice vectors
     const auto N  = G.size(); // number of reciprocal lattice vectors
@@ -115,7 +113,7 @@
         for(unsigned int j=i; j<N; j++)
         {
             const auto q = G[i] - G[j];
-            V_GG(i,j) = V(A0,m_per_au,atoms,n_atoms,q);
+            V_GG(i,j) = V(A0,m_per_au,atoms,q);
 
             // Copy elements to upper triangle of all other blocks
             V_GG(i+N, j) = V_GG(i, j+N) = V_GG(i+N, j+N) = V_GG(i,j);
@@ -149,7 +147,7 @@
         {
             for(unsigned int j=0;j<=i;j++)	
             {
-                H_GG(i,j) += Vso(atoms,G,n_atoms,k[ik],i,j,N);
+                H_GG(i,j) += Vso(atoms,G,k[ik],i,j,N);
             }
         }
 
@@ -175,8 +173,6 @@
         }
     }
 
-    free(atoms);
-
     return EXIT_SUCCESS;
 }/* end main */
 
@@ -185,16 +181,14 @@
  *
  * \param[in] atoms   atomic definitions
  * \param[in] G	      reciprocal lattice vectors
- * \param[in] n_atoms number of atoms in structure
  * \param[in] k       the electron momentum
  * \param[in] i	      index
  * \param[in] j       index
  * \param[in] N       number of reciprocal lattice vectors
  */
 std::complex<double>
-Vso(const atom                   *atoms,
+Vso(const std::vector<atom>      &atoms,
     const std::vector<arma::vec> &G,
-    const size_t                  n_atoms,
     arma::vec const              &k,
     const unsigned int            i,
     const unsigned int            j,
@@ -232,15 +226,15 @@
     // Potential term
     std::complex<double> v=0;				/* Initialise for sum	*/
 
-    for(unsigned int ia=0;ia<n_atoms;ia++)
+    for(auto const atom : atoms)
     {
-        const double q_dot_t = dot(q, atoms[ia].r);
-        const auto Lambda = lambda(atoms[ia].type);
+        const double q_dot_t = dot(q, atom.r);
+        const auto Lambda = lambda(atom.type);
         v += Lambda * exp(std::complex<double>(0.0,-q_dot_t)); // [QWWAD3, 15.81]
     }
 
     v *= vso;
-    v/=(double)(n_atoms);
+    v/=atoms.size();
 
     return v;
 }
diff -Nru qwwad-1.5.1+15~ubuntu15.10.1/src/qwwad_pp_superlattice.cpp qwwad-1.5.2+15~ubuntu15.10.1/src/qwwad_pp_superlattice.cpp
--- qwwad-1.5.1+15~ubuntu15.10.1/src/qwwad_pp_superlattice.cpp	2016-08-26 08:42:27.000000000 +0000
+++ qwwad-1.5.2+15~ubuntu15.10.1/src/qwwad_pp_superlattice.cpp	2016-09-02 13:30:29.000000000 +0000
@@ -46,17 +46,15 @@
 static std::complex<double>
 V(double           A0,
   double           m_per_au,
-  atom            *atoms,
-  atom            *atomsp,
-  int              n_atoms,
+  std::vector<atom> const &atoms,
+  std::vector<atom> const &atomsp,
   arma::vec const &g);
 
 static std::complex<double>
 VF(double           A0,
    double           F,
    double           q,
-   atom            *atoms,
-   int              n_atoms,
+   std::vector<atom> const &atoms,
    arma::vec const &g);
 
 static std::valarray<std::complex<double>> read_ank(int N,
@@ -73,8 +71,7 @@
 static void write_VF(double  A0,
                      double  F,
                      double  q,
-                     atom   *atoms,
-                     int     n_atoms);
+                     std::vector<atom> const &atoms);
 
 static void clean_Hdash(std::complex<double> *Hdash,
                         int                   order);
@@ -92,7 +89,6 @@
 int	INFO;		/* LAPACK: information integer			*/
 int	Nn;		/* number of bands in calculation		*/
 int	Nkxi;		/* number of k points in calculation		*/
-size_t	n_atoms;	/* number of atoms in (large) cell		*/
 int     n_min;          /* lowest output band                           */
 int     n_max;          /* highest output band                          */
 int	i;		/* loop index for matrix rows			*/
@@ -111,8 +107,6 @@
 char	p;		/* the particle					*/
 char	UPLO='L';	/* LAPACK: diagonalise `L'ower triangle 	*/
 FILE	*FExi;		/* pointer to output energy file `Exi.r'	*/
-atom	*atoms;		/* the type and position of the atoms		*/
-atom	*atomsp;	/* the type and position of the perturbed atoms	*/
 bool	o;		/* if set, output the Fourier Transform VF(g)	*/
 
 /* default values	*/
@@ -170,9 +164,9 @@
  argc--;
 }
 strcpy(filename,"atoms.xyz");
-atoms=read_atoms(&n_atoms,filename);	/* read in atomic basis	*/
+auto const atoms=read_atoms(filename);	/* read in atomic basis	*/
 strcpy(filename,"atomsp.xyz");
-atomsp=read_atoms(&n_atoms,filename);	/* read in perturbation	*/
+auto const atomsp=read_atoms(filename);	/* read in perturbation	*/
 
 auto G = read_rlv(A0); // read in reciprocal lattice vectors
 auto N = G.size(); // number of reciprocal lattice vectors
@@ -187,7 +181,7 @@
 
 /* Output the  Fourier Transform of the electric field	*/
 
-if(o) write_VF(A0,F,q,atoms,n_atoms);
+if(o) write_VF(A0,F,q,atoms);
 
 /* Allocate memory */
 
@@ -249,8 +243,8 @@
             )
             *
             (
-             V(A0,m_per_au,atoms,atomsp,n_atoms,g) +
-             VF(A0,F,q,atoms,n_atoms,g)
+             V(A0,m_per_au,atoms,atomsp,g) +
+             VF(A0,F,q,atoms,g)
             )
            );
    } /* end iG */
@@ -282,8 +276,6 @@
 free(Hdash);
 free(Exi);
 free(Enk);
-free(atoms);
-free(atomsp);
 
 return EXIT_SUCCESS;
 }/* end main */
@@ -492,15 +484,13 @@
  * \param m_per_au conversion factor from SI to a.u.
  * \param atoms    atomic definitions
  * \param atomsp   atomic definitions
- * \param n_atoms  number of atoms in structure
  * \param g        the vector, g=G'-G+kxi'-kxi
  */
 static std::complex<double>
 V(double           A0,
   double           m_per_au,
-  atom            *atoms,
-  atom            *atomsp,
-  int              n_atoms,
+  std::vector<atom> const &atoms,
+  std::vector<atom> const &atomsp,
   arma::vec const &g)
 {
  std::complex<double> v;     /* potential					*/
@@ -509,7 +499,8 @@
  v=0;
 
  // Sum over atoms [QWWAD4, 16.50]
- for(int ia=0;ia<n_atoms;ia++)
+ auto const n_atoms = atoms.size();
+ for(unsigned int ia=0;ia<n_atoms;ia++)
  {
      // general vector representing atom within cell
      auto const t = atoms[ia].r;
@@ -535,19 +526,17 @@
  * \param F       the electric field strength
  * \param q       the carrier charge
  * \param atoms   atomic definitions
- * \param n_atoms number of atoms in structure
  * \param g       the vector, g=G'-G+kxi'-kxi
  */
 static std::complex<double>
 VF(double           A0,
    double           F,
    double           q,
-   atom            *atoms,
-   int              n_atoms,
+   std::vector<atom> const &atoms,
    arma::vec const &g)
 {
     // Calculate the number of lattice constants in each superlattice period
-    int const n_z=n_atoms/4;
+    int const n_z=atoms.size()/4;
 
     /* The smallest reciprocal lattice vector is therefore pi/(n_z*A0), thus 
        anything less than this must be zero				*/
@@ -567,8 +556,8 @@
     else
     {
         // Get midpoint of unit cell
-        const auto z_first = atoms[0].r(2); // z-position of first atom
-        const auto z_last  = atoms[n_atoms-1].r(2); // z-position of last atom
+        const auto z_first = atoms.front().r(2); // z-position of first atom
+        const auto z_last  = atoms.back().r(2); // z-position of last atom
         double const z0=(z_last + z_first)/2;
 
         std::complex<double> v1;	/* first term in potential			*/
@@ -609,13 +598,11 @@
  * \param F       the electric field strength
  * \param q       the carrier charge
  * \param atoms   atomic definitions
- * \param n_atoms number of atoms in structure
  */
 static void write_VF(double  A0,
                      double  F,
                      double  q,
-                     atom   *atoms,
-                     int     n_atoms)
+                     std::vector<atom> const &atoms)
 {
  FILE	*FVFg;		/* pointer to output file	*/
  int	i;		/* index			*/
@@ -629,7 +616,7 @@
      g(1)=0;
      g(2)=((float)i*4/500)*pi/A0;
 
-     fprintf(FVFg,"%le %le\n",g(2)/(pi/A0),abs(VF(A0,F,q,atoms,n_atoms,g)));
+     fprintf(FVFg,"%le %le\n",g(2)/(pi/A0),abs(VF(A0,F,q,atoms,g)));
  }
 
  fclose(FVFg);