diff --git a/potentials/Si.tersoff.mod b/potentials/Si.tersoff.mod
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+# Modified Tersoff potential (named MOD potential) parameters for various elements and mixtures
+# multiple entries can be added to this file, LAMMPS reads the ones it needs
+# these entries are in LAMMPS "metal" units:
+#   A,B = eV; lambda1,lambda2 = 1/Angstroms; R,D = Angstroms
+#   other quantities are unitless
+
+# MOD. This is the Si parameterization from the paper:
+# [1] T. Kumagai, S. Izumi, S. Hara, S. Sakai, Comp. Mat. Sci., 39, 457 (2007) 
+
+# format of a single entry (one or more lines):
+#   element 1, element 2, element 3, 
+#   beta, alpha, h, eta, 
+#   beta_ters, lambda2, B, R, D, lambda1, A, n
+#   c1,  c2,  c3,  c4,  c5  
+
+# Notes
+# 1) beta_ters must be equal to 1.0
+# 2) R = (R1+R2)/2, where R1 and R2 determined at [1] (R1 = 2.7A, R2 = 3.3A)
+# 3) D = (R2-R1)/2, where R1 and R2 determined at [1] (R1 = 2.7A, R2 = 3.3A)
+# 4) n = 1.0/(2*delta), where delta determined at [1] (eta*delta = 0.53298909)
+
+#mod
+Si  Si  Si  1.0  2.3890327  -.365  1.0 
+            1.0    1.345797  121.00047  3.0   0.3   3.2300135  3281.5905  .93810551 
+            0.20173476  730418.72  1000000.0  1.0  26.0