diff --git a/static/js/data.js b/static/js/data.js
index aeb4ee7c..f7aee023 100644
--- a/static/js/data.js
+++ b/static/js/data.js
@@ -348,6 +348,9 @@ class dataFileBase {
         for (const ex of dat.excitations) {
           console.assert(Number.isNaN(ex.T1.valueOf()) | ex.T1 > 50 | ex.isUnsafe == true, "Must be unsafe", dat, ex)
         }
+        for (const ex of dat.excitations) {
+          console.assert(JSON.stringify(ex.initial)!==JSON.stringify(ex.final),"Final must be different to initial" dat, ex)
+        }
       }
     }
     return dat