--- branches/development/src/UseTheForce/ForceField.cpp	2010/12/31 18:31:56	1535
+++ branches/development/src/UseTheForce/ForceField.cpp	2011/11/22 20:38:56	1665
@@ -36,7 +36,8 @@
  * [1]  Meineke, et al., J. Comp. Chem. 26, 252-271 (2005).             
  * [2]  Fennell & Gezelter, J. Chem. Phys. 124, 234104 (2006).          
  * [3]  Sun, Lin & Gezelter, J. Chem. Phys. 128, 24107 (2008).          
- * [4]  Vardeman & Gezelter, in progress (2009).                        
+ * [4]  Kuang & Gezelter,  J. Chem. Phys. 133, 164101 (2010).
+ * [5]  Vardeman, Stocker & Gezelter, J. Chem. Theory Comput. 7, 834 (2011).
  */
  
 /**
@@ -448,18 +449,73 @@ namespace OpenMD {
   }
   
   NonBondedInteractionType* ForceField::getNonBondedInteractionType(const std::string &at1, const std::string &at2) {
+    
     std::vector<std::string> keys;
     keys.push_back(at1);
     keys.push_back(at2);    
-   
+    
     //try exact match first
     NonBondedInteractionType* nbiType = nonBondedInteractionTypeCont_.find(keys);
     if (nbiType) {
       return nbiType;
     } else {
-      //if no exact match found, try wild card match
-      return nonBondedInteractionTypeCont_.find(keys, wildCardAtomTypeName_);  
-    }    
+      AtomType* atype1;
+      AtomType* atype2;
+      std::vector<std::string> at1key;
+      at1key.push_back(at1);
+      atype1 = atomTypeCont_.find(at1key);
+      
+      std::vector<std::string> at2key;
+      at2key.push_back(at2);
+      atype2 = atomTypeCont_.find(at2key);
+      
+      // query atom types for their chains of responsibility
+      std::vector<AtomType*> at1Chain = atype1->allYourBase();
+      std::vector<AtomType*> at2Chain = atype2->allYourBase();
+      
+      std::vector<AtomType*>::iterator i;
+      std::vector<AtomType*>::iterator j;
+      
+      int ii = 0;
+      int jj = 0;
+      int nbiTypeScore;
+      
+      std::vector<std::pair<int, std::vector<std::string> > > foundNBI;
+      
+      for (i = at1Chain.begin(); i != at1Chain.end(); i++) {
+        jj = 0;
+        for (j = at2Chain.begin(); j != at2Chain.end(); j++) {
+          
+          nbiTypeScore = ii + jj;
+          
+          std::vector<std::string> myKeys;
+          myKeys.push_back((*i)->getName());
+          myKeys.push_back((*j)->getName());
+          
+          NonBondedInteractionType* nbiType = nonBondedInteractionTypeCont_.find(myKeys);
+          if (nbiType) {
+            foundNBI.push_back(std::make_pair(nbiTypeScore, myKeys));
+          }
+          jj++;
+        }
+        ii++;
+      }
+      
+      
+      if (foundNBI.size() > 0) {
+        // sort the foundNBI by the score:
+        std::sort(foundNBI.begin(), foundNBI.end());
+        
+        int bestScore = foundNBI[0].first;
+        std::vector<std::string> theKeys = foundNBI[0].second;
+        
+        NonBondedInteractionType* bestType = nonBondedInteractionTypeCont_.find(theKeys);        
+        return bestType;
+      } else {
+        //if no exact match found, try wild card match
+        return nonBondedInteractionTypeCont_.find(keys, wildCardAtomTypeName_);
+      }
+    }
   }
   
   BondType* ForceField::getExactBondType(const std::string &at1,