diff --git a/diffusivityModel/diffusivityModel/diffusivityModel.C b/diffusivityModel/diffusivityModel/diffusivityModel.C
index 51ddf7a..f823215 100644
--- a/diffusivityModel/diffusivityModel/diffusivityModel.C
+++ b/diffusivityModel/diffusivityModel/diffusivityModel.C
@@ -665,15 +665,8 @@ void Foam::diffusivityModel::correct()
 
     const PtrList<volScalarField> &Y(thermo_.composition().Y());
 
-    scalarField Wpure(species_.size());
-    forAll (Wpure, i)
-    {
-        Wpure[i] = thermo_.composition().W(i);
-    }
-
     scalarSymmetricSquareMatrix Dij(species_.size());
 
-    scalarField localX(species_.size());
     scalarField localY(species_.size());
 
     scalarField Di(species_.size());
@@ -694,7 +687,7 @@ void Foam::diffusivityModel::correct()
 
         GasState state (pi, Ti, localY);
 
-        localX = state.X();
+        const scalarField &localX = state.X();
 
         calculateMuD (muI, Dij, state);
 
@@ -734,7 +727,7 @@ void Foam::diffusivityModel::correct()
 
             GasState state (pi, Ti, localY);
 
-            localX = state.X();
+            const scalarField &localX = state.X();
 
             calculateMuD (muI, Dij, state);