.. DO NOT EDIT.
.. THIS FILE WAS AUTOMATICALLY GENERATED BY SPHINX-GALLERY.
.. TO MAKE CHANGES, EDIT THE SOURCE PYTHON FILE:
.. "api/gallery/photochem/photostationary_state/plot_01_photoswitch_pss.py"
.. LINE NUMBERS ARE GIVEN BELOW.

.. only:: html

    .. note::
        :class: sphx-glr-download-link-note

        :ref:`Go to the end <sphx_glr_download_api_gallery_photochem_photostationary_state_plot_01_photoswitch_pss.py>`
        to download the full example code.

.. rst-class:: sphx-glr-example-title

.. _sphx_glr_api_gallery_photochem_photostationary_state_plot_01_photoswitch_pss.py:


Photostationary-state kinetics of a two-state photoswitch
=============================================================

A photoswitch A <-> B under simultaneous forward and reverse photolysis
reaches a photostationary state (PSS) rather than running to completion.
:func:`~chemistrykit.photochem.systems.photostationary_state.photoswitch_network`
reuses :meth:`~chemistrykit.kinetics.systems.networks.StoichiometricNetwork.reversible`
directly, and :func:`~chemistrykit.photochem.systems.photostationary_state.photostationary_state`
gives the exact algebraic PSS composition -- checked here against direct
long-time numerical integration of the ODE system.

.. GENERATED FROM PYTHON SOURCE LINES 15-25

.. code-block:: Python

    import matplotlib.pyplot as plt

    from chemistrykit.photochem.systems.photostationary_state import (
        photostationary_ratio,
        photostationary_state,
        photoswitch_network,
        photoswitch_rate_constants,
    )
    from chemistrykit.photochem.visualizers.photochem_plots import plot_photostationary_approach








.. GENERATED FROM PYTHON SOURCE LINES 26-31

Rate constants from quantum yields and molar absorptivities (the
low-optical-density approximation -- see the module docstring). The
incident intensity I0 is left at a convenient normalized value (rather
than a literal photon flux) so the resulting pseudo-first-order rate
constants are O(1) on the plotted timescale below.

.. GENERATED FROM PYTHON SOURCE LINES 31-48

.. code-block:: Python

    phi_AB, eps_A = 0.55, 1.8e4
    phi_BA, eps_B = 0.30, 6.0e3
    I0 = 1.0e-4
    k_AB, k_BA = photoswitch_rate_constants(phi_AB, eps_A, phi_BA, eps_B, I0=I0)
    print(f"k_AB = {k_AB:.4f}, k_BA = {k_BA:.4f}")

    net = photoswitch_network(k_AB, k_BA, A0=1.0)
    result = net.integrate((0.0, 40.0), dt=1e-2, method="rk4")

    pss = photostationary_state(k_AB, k_BA, total_concentration=1.0)
    print(f"\nPSS ratio [B]/[A] (algebraic):  {pss.ratio_B_over_A:.4f}")
    print(f"PSS ratio [B]/[A] (long-time numeric): {result.concentration('B')[-1] / result.concentration('A')[-1]:.4f}")
    print(f"Sanity check (Fischer's formula): {photostationary_ratio(k_AB, k_BA):.4f}")

    ax = plot_photostationary_approach(result, pss)
    plt.tight_layout()
    plt.show()



.. image-sg:: /api/gallery/photochem/photostationary_state/images/sphx_glr_plot_01_photoswitch_pss_001.png
   :alt: Approach to the photostationary state
   :srcset: /api/gallery/photochem/photostationary_state/images/sphx_glr_plot_01_photoswitch_pss_001.png
   :class: sphx-glr-single-img


.. rst-class:: sphx-glr-script-out

 .. code-block:: none

    k_AB = 2.2800, k_BA = 0.4145

    PSS ratio [B]/[A] (algebraic):  5.5000
    PSS ratio [B]/[A] (long-time numeric): 5.5000
    Sanity check (Fischer's formula): 5.5000





.. rst-class:: sphx-glr-timing

   **Total running time of the script:** (0 minutes 0.282 seconds)


.. _sphx_glr_download_api_gallery_photochem_photostationary_state_plot_01_photoswitch_pss.py:

.. only:: html

  .. container:: sphx-glr-footer sphx-glr-footer-example

    .. container:: sphx-glr-download sphx-glr-download-jupyter

      :download:`Download Jupyter notebook: plot_01_photoswitch_pss.ipynb <plot_01_photoswitch_pss.ipynb>`

    .. container:: sphx-glr-download sphx-glr-download-python

      :download:`Download Python source code: plot_01_photoswitch_pss.py <plot_01_photoswitch_pss.py>`

    .. container:: sphx-glr-download sphx-glr-download-zip

      :download:`Download zipped: plot_01_photoswitch_pss.zip <plot_01_photoswitch_pss.zip>`


.. only:: html

 .. rst-class:: sphx-glr-signature

    `Gallery generated by Sphinx-Gallery <https://sphinx-gallery.github.io>`_