diff --git a/gdb9/README.md b/gdb9/README.md
index 69594cfb1..a57eb6abd 100644
--- a/gdb9/README.md
+++ b/gdb9/README.md
@@ -4,5 +4,6 @@ Notes on files
 - `diss/`: molecules that didn't survive geometry optimization (optg), i.e., dissociated into fragments.
 - `new.g/`: molecules whose connectivity changed after optg
 - `ni6/`: amons containing 6 heavy atoms
+  - The second line of `*.xyz` file corresponds to the total energy (in kcal/mol) calculated at the level of theory MOLPRO2018/DF-B3LYP/VTZ
 - `templ.com`: a template input file for optg by Molpro