Hydrogen-Bonding: Guanine–Cytosine Base Pair
====================================================

Usage
-----

The adf.rkf file for this example can be downloaded here:

1. **Download** :download:`GC_basepair.adf.rkf <./../../examples/ExamplesFromPaper/HydrogenBond/Guanine_Cytosine.rkf>`
2. Open the PyOrbb application.
3. Drag the .adf.rkf file to the GUI.

Now the most important interactions will appear. To further study
fragment orbitals that interact, the user will want to visualize the
orbitals:

4. Select the orbital of interest.
5. Click on the orbital (:math:`\varphi`).

Now the PyOrbb viewer window will open with many options for drawing
the orbitals.

Once the previous steps have been completed, the user should be able
to reproduce the following analysis [1]_ [2]_.




References
----------

.. [1] \ "The Nature of the Hydrogen Bond in DNA Base Pairs: The Role of Charge Transfer and Resonance Assistance," Chemistry - A European Journal 5 (1999): 3581–3594, `https://doi.org/10.1002/(sici)1521-3765(19991203)5:12<3581::aid-chem3581>3.0.co;2-y <https://doi.org/10.1002/(sici)1521-3765(19991203)5:12%3C3581::aid-chem3581%3E3.0.co;2-y>`_.
.. [2] |main art|