diff --git a/src/Determinants/slater_rules.irp.f b/src/Determinants/slater_rules.irp.f
index cf3b8c1e..16fe2adc 100644
--- a/src/Determinants/slater_rules.irp.f
+++ b/src/Determinants/slater_rules.irp.f
@@ -1248,17 +1248,18 @@ subroutine H_u_0(v_0,u_0,H_jj,n,keys_tmp,Nint)
   ASSERT (Nint > 0)
   ASSERT (Nint == N_int)
   ASSERT (n>0)
-  PROVIDE ref_bitmask_energy
+  PROVIDE ref_bitmask_energy davidson_criterion
+  v_0 = 0.d0
   !$OMP PARALLEL DEFAULT(NONE)                                       &
       !$OMP PRIVATE(i,hij,j,k,idx,jj,vt,ii,sh,sh2,ni,exa,ext,org_i,org_j,endi)                             &
-      !$OMP SHARED(n,H_jj,u_0,keys_tmp,Nint,v_0,davidson_threshold,sorted,shortcut,sort_idx,version,davidson_criterion_is_built)
+      !$OMP SHARED(n,H_jj,u_0,keys_tmp,Nint,v_0,davidson_threshold,sorted,shortcut,sort_idx,version)
   allocate(idx(0:n), vt(n))
   Vt = 0.d0
-  v_0 = 0.d0
   
   !$OMP SINGLE
   call sort_dets_ab_v(keys_tmp, sorted, sort_idx, shortcut, version, n, Nint)
   !$OMP END SINGLE
+  !$OMP BARRIER
   
   !$OMP DO SCHEDULE(dynamic)
   do sh=1,shortcut(0)
@@ -1298,9 +1299,11 @@ subroutine H_u_0(v_0,u_0,H_jj,n,keys_tmp,Nint)
   enddo
   !$OMP END DO
   
+  integer :: omp_get_num_threads , omp_get_thread_num
   !$OMP SINGLE
   call sort_dets_ba_v(keys_tmp, sorted, sort_idx, shortcut, version, n, Nint)
   !$OMP END SINGLE
+  !$OMP BARRIER
  
   !$OMP DO SCHEDULE(dynamic)
   do sh=1,shortcut(0)