docs: Document reaction attributes constant_pH and gamma

doc/sphinx/advanced_methods.rst

@@ -1707,7 +1707,7 @@ In the *forward* reaction, the appropriate number of reactants (given by
 :math:`\nu_i`) is removed from the system, and the concomitant number of
 products is inserted into the system. In the *backward* reaction,
 reactants and products exchange their roles. The acceptance probability
-:math:`P^{\xi}` for move from state :math:`o` to :math:`n` reaction
+:math:`P^{\xi}` for a move from state :math:`o` to :math:`n` in the reaction
 ensemble is given by the criterion :cite:`smith94c`
 
 .. math::
@@ -1718,10 +1718,11 @@ ensemble is given by the criterion :cite:`smith94c`
 
 where :math:`\Delta E=E_\mathrm{new}-E_\mathrm{old}` is the change in potential energy,
 :math:`V` is the simulation box volume,
-and :math:`\beta=1/k_\mathrm{B}T`.
-The extent of reaction, :math:`\xi=1` for the forward, and
+:math:`\beta=1/k_\mathrm{B}T` is the Boltzmann factor, and
+:math:`\xi` is the extent of reaction, with :math:`\xi=1` for the forward and
 :math:`\xi=-1` for the backward direction.
-The parameter :math:`\Gamma` proportional to the reaction constant. It is defined as
+
+:math:`\Gamma` is proportional to the reaction constant. It is defined as
 
 .. math::
 

src/python/espressomd/reaction_ensemble.py

@@ -298,8 +298,8 @@ def add_reaction(self, **kwargs):
         Parameters
         ----------
         gamma : :obj:`float`
-            Equilibrium constant of the reaction in simulation units, :math:`\\gamma` (see the User
-            guide, section 16.7.1. for the definition and further details).
+            Equilibrium constant :math:`\\Gamma` of the reaction in simulation
+            units (see section :ref:`Reaction Ensemble` for its definition).
         reactant_types : list of :obj:`int`
             List of particle types of reactants in the reaction.
         reactant_coefficients : list of :obj:`int`
@@ -398,6 +398,11 @@ class ConstantpHEnsemble(ReactionAlgorithm):
     are always assumed to be at index 0 of the lists passed to arguments
     ``reactant_types`` and ``product_types``.
 
+    Attributes
+    ----------
+    constant_pH : :obj:`float`
+        Constant pH value.
+
     """
     _so_name = "ReactionMethods::ConstantpHEnsemble"
     _so_creation_policy = "LOCAL"