diff --git a/stable/champ/save_for_champ.irp.f b/stable/champ/save_for_champ.irp.f
index d01d75f..0f9d267 100644
--- a/stable/champ/save_for_champ.irp.f
+++ b/stable/champ/save_for_champ.irp.f
@@ -65,11 +65,13 @@ program qmcpack
           enddo
           !$OMP PARALLEL DO DEFAULT(SHARED) PRIVATE(i,j,istate,hij) REDUCTION(+:F)
           do k=1,N_det
+            if (sum(coef(k,:)*coef(k,:))==0.d0) cycle
             call i_H_j(det(1,1,k), det(1,1,k), N_int, hij)
             do istate=1,N_states
               F(istate) = F(istate) + hij*coef(k,istate)*coef(k,istate)
             enddo
             do l=1,k-1
+              if (sum(coef(l,:)*coef(l,:))==0.d0) cycle
               call i_H_j(det(1,1,k), det(1,1,l), N_int, hij)
               do istate=1,N_states
                 F(istate) = F(istate) + 2.d0*hij*coef(k,istate)*coef(l,istate)