diff --git a/trex.org b/trex.org
index b1ad3df..b7c5723 100644
--- a/trex.org
+++ b/trex.org
@@ -124,7 +124,7 @@ arrays are 0-based. Hence, we introduce the ~index~ type which is an
   V_{A \ell}(\mathbf{r}) =
   \sum_{q=1}^{N_{q \ell}}
   \beta_{A q \ell}\, |\mathbf{r}-\mathbf{R}_{A}|^{n_{A q \ell}}\,
-  e^{-\alpha_{A q \ell} |\mathbf{r}-\mathbf{R}_A|^2 }}
+  e^{-\alpha_{A q \ell} |\mathbf{r}-\mathbf{R}_{A}|^2 }
   \]
   
   See http://dx.doi.org/10.1063/1.4984046 for more info.