Added methods to InterfaceKinetics to get effective rate parameters

Effective rate parameters are used in SurfaceArrhenius reactions.

Resolves #297.

include/cantera/kinetics/InterfaceKinetics.h

@@ -161,6 +161,43 @@ public:
     virtual void getRevRateConstants(doublereal* krev,
                                      bool doIrreversible = false);
 
+    //! Return effective preexponent for the specified reaction
+    /*!
+     *  Returns effective preexponent, accounting for surface coverage
+     *  dependencies.
+     *
+     *  @param irxn Reaction number in the kinetics mechanism
+     *  @return Effective preexponent
+     */
+    double effectivePreExponentialFactor(size_t irxn) {
+        return m_rates.effectivePreExponentialFactor(irxn);
+    }
+
+    //! Return effective activation energy for the specified reaction
+    /*!
+     *  Returns effective activation energy, accounting for surface coverage
+     *  dependencies.
+     *
+     *  @param irxn Reaction number in the kinetics mechanism
+     *  @return Effective activation energy divided by the gas constant
+     */
+    double effectiveActivationEnergy_R(size_t irxn) {
+       return m_rates.effectiveActivationEnergy_R(irxn);
+    }
+
+    //! Return effective temperature exponent for the specified reaction
+    /*!
+     *  Returns effective temperature exponenty, accounting for surface coverage
+     *  dependencies. Current parameterization in SurfaceArrhenius does not
+     *  change this parameter with the change in surface coverages.
+     *
+     *  @param irxn Reaction number in the kinetics mechanism
+     *  @return Effective temperature exponent
+     */
+    double effectiveTemperatureExponent(size_t irxn) {
+       return m_rates.effectiveTemperatureExponent(irxn);
+    }
+
     //! @}
     //! @name Reaction Mechanism Construction
     //! @{

include/cantera/kinetics/RateCoeffMgr.h

@@ -75,6 +75,44 @@ public:
         return m_rates.size();
     }
 
+    //! Return effective preexponent for the specified reaction.
+    /*!
+     *  Returns effective preexponent, accounting for surface coverage
+     *  dependencies. Used in InterfaceKinetics.
+     *
+     *  @param irxn Reaction number in the kinetics mechanism
+     *  @return Effective preexponent
+     */
+    double effectivePreExponentialFactor(size_t irxn) {
+        return m_rates[irxn].preExponentialFactor();
+    }
+
+    //! Return effective activation energy for the specified reaction.
+    /*!
+     *  Returns effective activation energy, accounting for surface coverage
+     *  dependencies. Used in InterfaceKinetics.
+     *
+     *  @param irxn Reaction number in the kinetics mechanism
+     *  @return Effective activation energy divided by the gas constant
+     */
+    double effectiveActivationEnergy_R(size_t irxn) {
+        return m_rates[irxn].activationEnergy_R();
+    }
+
+    //! Return effective temperature exponent for the specified  reaction.
+    /*!
+     *  Returns effective temperature exponent, accounting for surface coverage
+     *  dependencies. Used in InterfaceKinetics. Current parameterization in
+     *  SurfaceArrhenius does not change this parameter with the change in
+     *  surface coverages.
+     *
+     *  @param irxn Reaction number in the kinetics mechanism
+     *  @return Effective temperature exponent
+     */
+    double effectiveTemperatureExponent(size_t irxn) {
+        return m_rates[irxn].temperatureExponent();
+    }
+
 protected:
     std::vector<R> m_rates;
     std::vector<size_t> m_rxn;

include/cantera/kinetics/RxnRates.h

@@ -118,7 +118,7 @@ public:
     explicit SurfaceArrhenius(double A, double b, double Ta);
 
     //! Add a coverage dependency for species *k*, with pre-exponential
-    //! dependence *a*, temperature exponent dependence *m* and activation
+    //! dependence *a*, rate constant exponential dependency *m*, and activation
     //! energy dependence *e*, where *e* is in Kelvin, i.e. energy divided by
     //! the molar gas constant.
     void addCoverageDependence(size_t k, doublereal a,
@@ -153,6 +153,22 @@ public:
                               (m_E + m_ecov)*recipT + m_mcov);
     }
 
+    //! Return the pre-exponential factor *A* (in m, kmol, s to powers depending
+    //! on the reaction order) accounting coverage dependence.
+    /*!
+     *  Returns reaction prexponent accounting for both *a* and *m*.
+     */
+    doublereal preExponentialFactor() const {
+        return m_A * std::exp(std::log(10.0)*m_acov + m_mcov);
+    }
+
+    //! Return effective temperature exponent
+    doublereal temperatureExponent() const {
+        return m_b;
+    }
+
+    //! Return the activation energy divided by the gas constant (i.e. the
+    //! activation temperature) [K], accounting coverage dependence.
     doublereal activationEnergy_R() const {
         return m_E + m_ecov;
     }

src/kinetics/RxnRates.cpp

@@ -21,7 +21,7 @@ Arrhenius::Arrhenius(doublereal A, doublereal b, doublereal E)
     if (m_A  <= 0.0) {
         m_logA = -1.0E300;
     } else {
-        m_logA = log(m_A);
+        m_logA = std::log(m_A);
     }
 }