diff --git a/doc/pair_tersoff.txt b/doc/pair_tersoff.txt
index 840598dfa7..2fd533c62a 100644
--- a/doc/pair_tersoff.txt
+++ b/doc/pair_tersoff.txt
@@ -121,6 +121,8 @@ which we will refer to as Tersoff_2 potential
 "(Tersoff_2)"_#Tersoff_2.
 
 LAMMPS parameter values for Tersoff_2 can be obtained as follows. 
+gamma = 1, jst as for Tersoff_1, but now lambda3 = 0 and 
+the value of m has no effect.
 The parameters for species i and j can be calculated 
 using the Tersoff_2 mixing rules: