double precision function gscreen(distij,distik,distjk,reall)
  !La  fonction ecran  electronique
  implicit none
  double precision :: distij,distik,distjk,reall
  gscreen=distij**2/2.+distik**3/3.+distjk**3/3.
  gscreen=0.0d0
  return
end function gscreen

double precision function d1gscreen(distij,distik,distjk,reall)
  !La derivee/la premiere variable de la fonction ecran  electronique
  implicit none
  double precision :: distij,distik,distjk,reall
  d1gscreen=distij
  d1gscreen=0.0d0
  return
end function d1gscreen

double precision function d2gscreen(distij,distik,distjk,reall)
  !La derivee/la seconde variable de la fonction ecran  electronique
  implicit none
  double precision :: distij,distik,distjk,reall
  d2gscreen=distik**2
  d2gscreen=0.0d0
  return
end function d2gscreen

double precision function d3gscreen(distij,distik,distjk,reall)
  !La derivee/la troisieme variable de la fonction ecran  electronique
  implicit none
  double precision :: distij,distik,distjk,reall
  d3gscreen=distjk**2
  d3gscreen=0.0d0
  return
end function d3gscreen