diff --git a/unittest/force-styles/tests/improper-harmonic.yaml b/unittest/force-styles/tests/improper-harmonic.yaml
index a7d2d44b64..7b2e14ee9e 100644
--- a/unittest/force-styles/tests/improper-harmonic.yaml
+++ b/unittest/force-styles/tests/improper-harmonic.yaml
@@ -15,7 +15,7 @@ improper_coeff: ! |
   2  45.0  59.5
 extract: ! |
   k 1
-  chi 1
+  chi0 1
 natoms: 29
 init_energy: 369.34096479618404
 init_stress: ! |2-