diff --git a/external/irpf90 b/external/irpf90
index 43160c60..4ab1b175 160000
--- a/external/irpf90
+++ b/external/irpf90
@@ -1 +1 @@
-Subproject commit 43160c60d88d9f61fb97cc0b35477c8eb0df862b
+Subproject commit 4ab1b175fc7ed0d96c1912f13dc53579b24157a6
diff --git a/plugins/local/extra_basis_int/coul_1s.irp.f b/plugins/local/extra_basis_int/coul_1s.irp.f
index 964ed36a..62ec4331 100644
--- a/plugins/local/extra_basis_int/coul_1s.irp.f
+++ b/plugins/local/extra_basis_int/coul_1s.irp.f
@@ -11,6 +11,11 @@ double precision function coul_full_ao_pq_r_1s(p,q,R,R_p,R_q)
  double precision, intent(in) :: R(3),R_p(3),R_q(3)
  integer, intent(in) :: p,q
  double precision :: coef,dist,P_pq(3),coefaos
+ if(.not.ao_extra_only_1s)then
+   print*,'You are using a function assuming that the extra basis is fitted on 1s functions'
+   print*,'But this is not the case apparently ... stopping'
+   stop
+ endif
  coefaos= ao_extra_coef_normalized(p,1) * ao_extra_coef_normalized(q,1) 
  coef = inv_pi_gamma_pq_3_2_ao_extra(p,q) * E_pq_ao_extra(p,q)
  P_pq = ao_extra_expo(p,1) * R_p + ao_extra_expo(q,1) * R_q
@@ -40,6 +45,11 @@ double precision function coul_pq_r_1s(p,q,R,R_p,R_q)
  double precision, intent(in) :: R(3),R_p(3),R_q(3)
  integer, intent(in) :: p,q
  double precision :: dist,P_pq(3)
+ if(.not.ao_extra_only_1s)then
+   print*,'You are using a function assuming that the extra basis is fitted on 1s functions'
+   print*,'But this is not the case apparently ... stopping'
+   stop
+ endif
  P_pq = ao_extra_expo(p,1) * R_p + ao_extra_expo(q,1) * R_q
  P_pq = P_pq * inv_gamma_pq_ao_extra(q,p)
  dist = (P_pq(1)-R(1)) * (P_pq(1)-R(1))
diff --git a/plugins/local/extra_basis_int/pot_ao_ints.irp.f b/plugins/local/extra_basis_int/pot_ao_ints.irp.f
index 1828f980..5a7d7580 100644
--- a/plugins/local/extra_basis_int/pot_ao_ints.irp.f
+++ b/plugins/local/extra_basis_int/pot_ao_ints.irp.f
@@ -3,23 +3,45 @@ BEGIN_PROVIDER [ double precision, pot_vne_A_extra_basis, (ao_extra_num,ao_extra
   BEGIN_DOC
   !
   ! Computes the following integral :
-  ! $\sum_{R in nuclei} -Z <chi_i|1/|r-R||chi_j>$ 
+  ! $\sum_{R in the USUAL nuclei} -Z <chi_i|1/|r-R||chi_j>$ 
   !
   !
-  ! where $\chi_i(r)$ AND $\chi_j(r)$ belongs to the extra basis 
+  ! where $\chi_i(r)$ AND $\chi_j(r)$ belongs to the EXTRA basis 
   END_DOC
-  integer :: mu,nu,k_nucl
-  double precision :: mu_in, R_nucl(3),charge_nucl, integral
-  double precision :: NAI_pol_mult_erf_ao_extra
-  mu_in = 10.d0**10
+  integer :: mu,nu
+  double precision :: v_nucl_extra_ao
   pot_vne_A_extra_basis = 0.d0
   do mu = 1, ao_extra_num
    do nu = 1, ao_extra_num
-    do k_nucl = 1, nucl_num
-     R_nucl(1:3) = nucl_coord_transp(1:3,k_nucl)
-     charge_nucl = nucl_charge(k_nucl)
-     integral = NAI_pol_mult_erf_ao_extra(mu, nu, mu_in, R_nucl)
-     pot_vne_A_extra_basis(nu,mu) += -integral * charge_nucl
+    pot_vne_A_extra_basis(nu,mu)= v_nucl_extra_ao(mu,nu)
+   enddo
+  enddo
+
+END_PROVIDER 
+
+
+BEGIN_PROVIDER [ double precision, pot_vne_extra_basis, (ao_num,ao_num)]
+ implicit none
+  BEGIN_DOC
+  !
+  ! Computes the following integral :
+  ! $\sum_{R in EXTRA nuclei} -Z <chi_i|1/|r-R||chi_j>$ 
+  !
+  !
+  ! where $\chi_i(r)$ AND $\chi_j(r)$ belongs to the USUAL basis 
+  END_DOC
+  integer :: mu,nu,k_nucl
+  double precision :: mu_in, R_nucl(3),charge_nucl, integral
+  double precision :: NAI_pol_mult_erf_ao
+  mu_in = 10.d0**10
+  pot_vne_extra_basis = 0.d0
+  do mu = 1, ao_num
+   do nu = 1, ao_num
+    do k_nucl = 1, extra_nucl_num
+     R_nucl(1:3) = extra_nucl_coord_transp(1:3,k_nucl)
+     charge_nucl = extra_nucl_charge(k_nucl)
+     integral = NAI_pol_mult_erf_ao(mu, nu, mu_in, R_nucl)
+     pot_vne_extra_basis(nu,mu) += -integral * charge_nucl
     enddo
    enddo
   enddo
diff --git a/plugins/local/extra_basis_int/v_mixed_extra.irp.f b/plugins/local/extra_basis_int/v_mixed_extra.irp.f
index ac856692..15958ab5 100644
--- a/plugins/local/extra_basis_int/v_mixed_extra.irp.f
+++ b/plugins/local/extra_basis_int/v_mixed_extra.irp.f
@@ -1,3 +1,6 @@
+!!! TODO:: optimize when "ao_extra_only_1s" is True
+
+
 double precision function v_extra_nucl_extra_ao(i_ao,j_ao)
  implicit none
   BEGIN_DOC
@@ -23,6 +26,30 @@ double precision function v_extra_nucl_extra_ao(i_ao,j_ao)
  enddo
 end
 
+double precision function v_extra_nucl_ao(i_ao,j_ao)
+ implicit none
+  BEGIN_DOC
+  !
+  ! Computes the following integral :
+  ! $\int_{-\infty}^{infty} dr \chi_i(r) \chi_j(r) v_ne(r)$.
+  !
+  !
+  ! where BOTH $\chi_i(r)$ AND $\chi_j(r)$ belongs to the REGULAR basis 
+  !
+  ! and v_ne(r) is the Coulomb potential coming from the EXTRA nuclei
+  END_DOC
+ integer, intent(in) ::i_ao,j_ao
+ integer :: i
+ double precision :: mu_in, coord(3),charge, integral
+ double precision :: NAI_pol_mult_erf_ao
+ mu_in = 1.d+10
+ do i = 1, extra_nucl_num
+  coord(1:3) = extra_nucl_coord_transp(1:3,i)
+  charge = extra_nucl_charge(i)
+  v_extra_nucl_ao += -NAI_pol_mult_erf_ao(i_ao, j_ao, mu_in, coord) * charge
+ enddo
+end
+
 
 double precision function v_nucl_extra_ao(i_ao,j_ao)
  implicit none
diff --git a/src/ao_extra_basis/fit_1s_basis.irp.f b/src/ao_extra_basis/fit_1s_basis.irp.f
index ef09d5b2..9c788173 100644
--- a/src/ao_extra_basis/fit_1s_basis.irp.f
+++ b/src/ao_extra_basis/fit_1s_basis.irp.f
@@ -31,6 +31,7 @@ program fit_1s_basis
  call ezfio_set_extra_nuclei_extra_nucl_label(new_nucl_label_1s)
 !
  call ezfio_set_ao_extra_basis_ao_extra_num(n_func_tot)
+ call ezfio_set_ao_extra_basis_ao_extra_only_1s(.True.)
  call ezfio_set_ao_extra_basis_ao_extra_center(ao_extra_center)
  call ezfio_set_ao_extra_basis_ao_extra_nucl(new_ao_nucl_1s)
  call ezfio_set_ao_extra_basis_ao_extra_prim_num(new_ao_prim_num_1s)