Ternary Chemical Activation Reaction
====================================

Ternary Chemical Activation reaction rate constant equations take the form:

.. math::

   \frac{k_0}{1 + \frac{k_0[\mathrm{M}]}{k_{\infty}}} F_C^{\left(1 + \frac{1}{N} [\log_{10}(\frac{k_0[\mathrm{M}]}{k_{\infty}})]^2\right)^{-1}}

where:

- :math:`k_0` is the low-pressure limiting rate constant (:math:`(\mbox{mol}\,\mathrm{m}^{-3})^{-(n-1)}\,\mathrm{s}^{-1}`),
- :math:`k_{\infty}` is the high-pressure limiting rate constant (:math:`(\mbox{mol}\,\mathrm{m}^{-3})^{-(n-1)}\,\mathrm{s}^{-1}`),
- :math:`[\mathrm{M}]` is the density of air (:math:`\mathrm{mol}\,\mathrm{m}^{-3}`),
- :math:`F_C` and :math:`N` are parameters that determine the shape of the fall-off curve,
  and are typically 0.6 and 1.0, respectively :cite:`JPL15`.

:math:`k_0` and :math:`k_{\infty}` are calculated as `Arrhenius` rate constants with :math:`D=300` and :math:`E=0`.

Input data for Ternary Chemical Activation reactions have the following format:

.. tab-set::

    .. tab-item:: YAML

        .. code-block:: yaml

            type: TERNARY_CHEMICAL_ACTIVATION
            name: foo-ternary
            k0_A: 5.6e-12
            k0_B: -1.8
            k0_C: 180.0
            kinf_A: 3.4e-12
            kinf_B: -1.6
            kinf_C: 104.1
            Fc: 0.7
            N: 0.9
            gas phase: gas
            reactants:
                - species name: foo
                - species name: bar
                  coefficient: 2
            products:
                - species name: baz
                - species name: qux
                  coefficient: 0.65


    .. tab-item:: JSON

        .. code-block:: json

            {
              "type": "TERNARY_CHEMICAL_ACTIVATION",
              "name": "foo-ternary",
              "k0_A": 5.6e-12,
              "k0_B": -1.8,
              "k0_C": 180.0,
              "kinf_A": 3.4e-12,
              "kinf_B": -1.6,
              "kinf_C": 104.1,
              "Fc": 0.7,
              "N": 0.9,
              "gas phase": "gas",
              "reactants": [
                {
                  "species name": "foo"
                },
                {
                  "species name": "bar",
                  "coefficient": 2
                }
              ],
              "products": [
                {
                  "species name": "baz"
                },
                {
                  "species name": "qux",
                  "coefficient": 0.65
                }
              ]
            }

The key-value pairs ``reactants`` and ``products`` are required. When a ``coefficient`` is not
specified for a reactant or product, it is assumed to be 1.0.

The ``gas phase`` key is required and must be set to the name of the phase the reaction
takes place in. The reactants and products must be present in the specified phase.

The two sets of parameters beginning with ``k0_`` and ``kinf_`` are the `Arrhenius` parameters for the
:math:`k_0` and :math:`k_{\infty}` rate constants, respectively. When not present, ``_A`` parameters are
assumed to be 1.0, ``_B`` to be 0.0, ``_C`` to be 0.0, ``Fc`` to be 0.6, and ``N`` to be 1.0.

Rate constants are in units of :math:`\mathrm{(m^{3}\ mol^{-1})^{(n-1)}\ s^{-1}}` where :math:`n` is the total number of reactants.