[docs] Fix math formatting

An excessive number of white spaces prevents proper rendering of
mathematical expressions.

include/cantera/thermo/PDSS_SSVol.h

@@ -53,53 +53,53 @@ namespace Cantera
  *   - This standard state model is invoked with the keyword "density_temperature_polynomial".
  *     The standard state density, which is the inverse of the volume,
  *     is considered a function of temperature only.
- *    \f[
+ *     \f[
  *       {\rho}^o_k(T,P) = \frac{M_k}{V^o_k(T,P)} = a_0 + a_1 T + a_2 T^2 + a_3 T^3
- *    \f]
+ *     \f]
  *
  * ## Specification of Species Standard State Properties
  *
  * The standard molar Gibbs free energy for species *k* is determined from
  * the enthalpy and entropy expressions
  *
- *       \f[
+ * \f[
  *            G^o_k(T,P) = H^o_k(T,P) - S^o_k(T,P)
- *       \f]
+ * \f]
  *
  * The enthalpy is calculated mostly from the MultiSpeciesThermo object's enthalpy
  * evaluator. The dependence on pressure originates from the Maxwell relation
  *
- *       \f[
+ * \f[
  *            {\left(\frac{dH^o_k}{dP}\right)}_T = T  {\left(\frac{dS^o_k}{dP}\right)}_T + V^o_k
- *       \f]
+ * \f]
  * which is equal to
  *
- *       \f[
+ * \f[
  *            {\left(\frac{dH^o_k}{dP}\right)}_T =  V^o_k -  T  {\left(\frac{dV^o_k}{dT}\right)}_P
- *       \f]
+ * \f]
  *
  * The entropy is calculated mostly from the MultiSpeciesThermo objects entropy
  * evaluator. The dependence on pressure originates from the Maxwell relation:
  *
- *       \f[
+ * \f[
  *              {\left(\frac{dS^o_k}{dP}\right)}_T =  - {\left(\frac{dV^o_k}{dT}\right)}_P
- *       \f]
+ * \f]
  *
  * The standard state constant-pressure heat capacity expression is obtained
  * from taking the temperature derivative of the Maxwell relation involving the
  * enthalpy given above to yield an expression for the pressure dependence of
  * the heat capacity.
  *
- *       \f[
+ * \f[
  *            {\left(\frac{d{C}^o_{p,k}}{dP}\right)}_T =  - T  {\left(\frac{{d}^2{V}^o_k}{{dT}^2}\right)}_T
- *       \f]
+ * \f]
  *
  * The standard molar Internal Energy for species *k* is determined from the
  * following relation.
  *
- *       \f[
+ * \f[
  *            U^o_k(T,P) = H^o_k(T,P) - p V^o_k
- *       \f]
+ * \f]
  *
  * An example of the specification of a standard state using a temperature dependent
  * standard state volume is given in the

include/cantera/thermo/PengRobinson.h

@@ -136,7 +136,7 @@ class PengRobinson : public MixtureFugacityTP
     //! Calculate species-specific critical temperature
     /*!
      *  The temperature dependent parameter in P-R EoS is calculated as
-     *       \f[ T_{crit} = (0.0778 a)/(0.4572 b R) \f]
+     * \f[ T_{crit} = (0.0778 a)/(0.4572 b R) \f]
      *  Units: Kelvin
      *
      * @param a    species-specific coefficients used in P-R EoS

include/cantera/thermo/StoichSubstance.h

@@ -39,20 +39,20 @@ namespace Cantera
  *
  * The enthalpy function is given by the following relation.
  *
- *       \f[
+ * \f[
  *              h^o_k(T,P) =
  *                  h^{ref}_k(T) + \tilde v \left( P - P_{ref} \right)
- *       \f]
+ * \f]
  *
  * For an incompressible, stoichiometric substance, the molar internal energy is
  * independent of pressure. Since the thermodynamic properties are specified by
  * giving the standard-state enthalpy, the term \f$ P_{ref} \tilde v\f$ is
  * subtracted from the specified reference molar enthalpy to compute the molar
  * internal energy.
  *
- *       \f[
+ * \f[
  *            u^o_k(T,P) = h^{ref}_k(T) - P_{ref} \tilde v
- *       \f]
+ * \f]
  *
  * The standard state heat capacity and entropy are independent of pressure. The
  * standard state Gibbs free energy is obtained from the enthalpy and entropy

include/cantera/thermo/SurfPhase.h

@@ -159,9 +159,9 @@ class SurfPhase : public ThermoPhase
      * be equal to the actual concentrations, \f$ C^s_k \f$. Activity
      * concentrations are
      *
-     *      \f[
+     * \f[
      *            C^a_k = C^s_k = \frac{\theta_k  n_0}{s_k}
-     *      \f]
+     * \f]
      *
      * where \f$ \theta_k \f$ is the surface site fraction for species k,
      * \f$ n_0 \f$ is the surface site density for the phase, and
@@ -185,9 +185,9 @@ class SurfPhase : public ThermoPhase
      * (that is, generalized) concentration. For this phase, the standard
      * concentration is species- specific
      *
-     *        \f[
+     * \f[
      *            C^0_k = \frac{n_0}{s_k}
-     *        \f]
+     * \f]
      *
      * This definition implies that the activity is equal to \f$ \theta_k \f$.
      *

include/cantera/thermo/ThermoPhase.h

@@ -509,9 +509,9 @@ class ThermoPhase : public Phase
      *  species k in a phase p, \f$ \zeta_k \f$, is related to the chemical
      *  potential via the following equation,
      *
-     *       \f[
+     * \f[
      *            \zeta_{k}(T,P) = \mu_{k}(T,P) + F z_k \phi_p
-     *       \f]
+     * \f]
      *
      * @param mu  Output vector of species electrochemical
      *            potentials. Length: m_kk. Units: J/kmol

include/cantera/thermo/WaterProps.h

@@ -29,9 +29,9 @@ class PDSS_Water;
  * The electrochemical potential of species \f$k\f$ in a phase \f$p\f$, \f$ \zeta_k \f$,
  * is related to the chemical potential via the following equation,
  *
- *       \f[
+ * \f[
  *            \zeta_{k}(T,P) = \mu_{k}(T,P) + z_k \phi_p
- *       \f]
+ * \f]
  *
  * where  \f$ \nu_k \f$ is the charge of species \f$k\f$, and \f$ \phi_p \f$ is
  * the electric potential of phase \f$p\f$.
@@ -46,9 +46,9 @@ class PDSS_Water;
  * Note, the overall electrochemical potential of a phase may not be changed
  * by the potential because many phases enforce charge neutrality:
  *
- *       \f[
+ * \f[
  *            0 = \sum_k z_k X_k
- *       \f]
+ * \f]
  *
  * Whether charge neutrality is necessary for a phase is also specified within
  * the ThermoPhase object, by the function call