diff --git a/docs/tutorials/04-lucj.ipynb b/docs/tutorials/04-lucj.ipynb
index 6c7e12113..9b013c177 100644
--- a/docs/tutorials/04-lucj.ipynb
+++ b/docs/tutorials/04-lucj.ipynb
@@ -16,10 +16,12 @@
    "outputs": [],
    "source": [
     "import pyscf\n",
+    "import pyscf.mcscf\n",
     "import ffsim\n",
     "\n",
     "# Build a stretched ethene molecule\n",
-    "a = 1.339\n",
+    "bond_distance = 2.678\n",
+    "a = 0.5 * bond_distance\n",
     "b = a + 0.5626\n",
     "c = 0.9289\n",
     "mol = pyscf.gto.Mole()\n",