diff --git a/README.md b/README.md
index 3481652..b491fc7 100644
--- a/README.md
+++ b/README.md
@@ -67,7 +67,7 @@ These last two programs use the parameters returned by radiations_fields.py in i
 
 2 files categories are usefull to run the programs :
 
-1. First, cross-section data of each PAH for sizes ranging from minimum 24 C atoms to 66 C atoms with associated energy for each charge state of the molecule.  
+1. First, cross-section data (in Mb) of each PAH for sizes ranging from minimum 24 C atoms to 66 C atoms with associated energy (in eV) for each charge state of the molecule.  
 Here you can find :
     1. the anions file
     2. the neutrals file
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