diff --git a/src/gridtools/ConvertToFES.cpp b/src/gridtools/ConvertToFES.cpp
index b419a66c1d67054f391a39427c2502190e39392f..ae0e473a0bde68ed853f09b03ae0b23ad71d86ef 100644
--- a/src/gridtools/ConvertToFES.cpp
+++ b/src/gridtools/ConvertToFES.cpp
@@ -32,7 +32,7 @@ This action allows you to take a free energy surface that was calculated using t
 action and to convert it to a free energy surface.  This transformation performed by doing:
 
 \f[
-F(x) = -k_B T \ln H(x)\f$
+F(x) = -k_B T \ln H(x)
 \f]
 
 The free energy calculated on a grid is output by this action and can be printed using \ref DUMPGRID