diff --git a/tools/tabulate/dihedral_harmonic_tabulate.py b/tools/tabulate/dihedral_harmonic_tabulate.py
index 29fc59dad2..8f49062e43 100755
--- a/tools/tabulate/dihedral_harmonic_tabulate.py
+++ b/tools/tabulate/dihedral_harmonic_tabulate.py
@@ -5,11 +5,11 @@ from tabulate import DihedralTabulate
 ################################################################################
 import math
 
-def harmonic_energy(theta):
+def harmonic_energy(phi):
     k = 100.0
     # the force constant in LAMMPS is in energy per radians^2 so convert from degrees to radians
     deg2rad = math.pi / 180.0
-    f = k * (1 - math.cos(2.0 * deg2rad * theta))
+    f = k * (1 - math.cos(2.0 * deg2rad * phi))
     return f
 
 ################################################################################