diff --git a/org/qmckl_local_energy.org b/org/qmckl_local_energy.org
index 8c11315..7076b31 100644
--- a/org/qmckl_local_energy.org
+++ b/org/qmckl_local_energy.org
@@ -1558,11 +1558,14 @@ integer function qmckl_compute_drift_vector_f(context, walk_num, &
     do imo = 1, beta_num
     do ielec = 1, beta_num
       mo_id = mo_index_beta(imo, iwalk, idet)
-      r_drift(1,ielec,iwalk) = r_drift(1,ielec,iwalk) + 2.0d0 * det_inv_matrix_beta(imo, ielec, iwalk, idet) * &
+      r_drift(1,alpha_num + ielec,iwalk) = r_drift(1,alpha_num + ielec,iwalk) + &
+                                    2.0d0 * det_inv_matrix_beta(imo, ielec, iwalk, idet) * &
                                     mo_vgl(mo_id, alpha_num + ielec, 2)
-      r_drift(2,ielec,iwalk) = r_drift(2,ielec,iwalk) + 2.0d0 * det_inv_matrix_beta(imo, ielec, iwalk, idet) * &
+      r_drift(2,alpha_num + ielec,iwalk) = r_drift(2,alpha_num + ielec,iwalk) + &
+                                    2.0d0 * det_inv_matrix_beta(imo, ielec, iwalk, idet) * &
                                     mo_vgl(mo_id, alpha_num + ielec, 3)
-      r_drift(3,ielec,iwalk) = r_drift(3,ielec,iwalk) + 2.0d0 * det_inv_matrix_beta(imo, ielec, iwalk, idet) * &
+      r_drift(3,alpha_num + ielec,iwalk) = r_drift(3,alpha_num + ielec,iwalk) + &
+                                    2.0d0 * det_inv_matrix_beta(imo, ielec, iwalk, idet) * &
                                     mo_vgl(mo_id, alpha_num + ielec, 4)
     end do
     end do