diff --git a/src/lagrangian/molecularDynamics/molecule/molecule/molecule.C b/src/lagrangian/molecularDynamics/molecule/molecule/molecule.C
index 88b6a8813b..ea7d52771c 100644
--- a/src/lagrangian/molecularDynamics/molecule/molecule/molecule.C
+++ b/src/lagrangian/molecularDynamics/molecule/molecule/molecule.C
@@ -54,7 +54,7 @@ bool molecule::move(molecule::trackData& td)
                 U_ += 0.5*deltaT*A_;
             }
 
-            while (td.keepParticle && !td.switchProcessor && tEnd > (SMALL*SMALL))
+            while (td.keepParticle && !td.switchProcessor && tEnd > ROOTVSMALL)
             {
                 // set the lagrangian time-step
                 scalar dt = min(dtMax, tEnd);