From a0b61d17b56a0ebbbce5ac33dd6c7ea970d5ab83 Mon Sep 17 00:00:00 2001
From: DallasTrinkle <dtrinkle@illinois.edu>
Date: Fri, 28 Apr 2017 15:08:59 -0500
Subject: [PATCH] Updates to documentation: equation.

---
 doc/src/Eqs/pair_meam_spline_multicomponent.tex | 13 +++++++++++++
 doc/src/pair_meam_spline.txt                    | 12 +++++++++++-
 2 files changed, 24 insertions(+), 1 deletion(-)
 create mode 100644 doc/src/Eqs/pair_meam_spline_multicomponent.tex

diff --git a/doc/src/Eqs/pair_meam_spline_multicomponent.tex b/doc/src/Eqs/pair_meam_spline_multicomponent.tex
new file mode 100644
index 0000000000..80296266d9
--- /dev/null
+++ b/doc/src/Eqs/pair_meam_spline_multicomponent.tex
@@ -0,0 +1,13 @@
+\documentclass[12pt]{article}
+
+\begin{document}
+
+$$
+   E=\sum_{i<j}\phi_{ij}(r_{ij})+\sum_{i}U_i(n_{i}),
+$$
+
+$$
+   n_{i}=\sum_{j\ne i}\rho_j(r_{ij})+\sum_{\substack{j<k,\\j,k\neq i}}fi_{j}(r_{ij})f_{k}(r_{ik})g_{jk}[\cos(\theta_{jik})]
+$$
+
+\end{document}
diff --git a/doc/src/pair_meam_spline.txt b/doc/src/pair_meam_spline.txt
index a02125a6d9..6d180f2391 100644
--- a/doc/src/pair_meam_spline.txt
+++ b/doc/src/pair_meam_spline.txt
@@ -23,7 +23,8 @@ pair_coeff * * Ti.meam.spline Ti Ti Ti :pre
 
 The {meam/spline} style computes pairwise interactions for metals
 using a variant of modified embedded-atom method (MEAM) potentials
-"(Lenosky)"_#Lenosky1.  The total energy E is given by
+"(Lenosky)"_#Lenosky1.  For a single species ("old-style") MEAM,
+the total energy E is given by
 
 :c,image(Eqs/pair_meam_spline.jpg)
 
@@ -31,6 +32,15 @@ where rho_i is the density at atom I, theta_jik is the angle between
 atoms J, I, and K centered on atom I. The five functions Phi, U, rho,
 f, and g are represented by cubic splines.
 
+The {meam/spline} style also supports a new style multicomponent
+modified embedded-atom method (MEAM) potential, where the total energy
+E is given by
+
+:c,image(Eqs/pair_meam_spline_multicomponent.jpg)
+
+where the five functions Phi, U, rho, f, and g depend on the chemistry
+of the atoms in the interaction. 
+
 The cutoffs and the coefficients for these spline functions are listed
 in a parameter file which is specified by the
 "pair_coeff"_pair_coeff.html command.  Parameter files for different