Further rewriting documentation

Author: ifilot

docs/becke_grid_analysis.rst

@@ -45,31 +45,4 @@ method.
 	:linenos:
 	:emphasize-lines: 14
 
-.. image:: _static/img/user_interface/06-grid-points.png
-
-Electron density and its gradient
----------------------------------
-
-The :class:`pydft.DFT` class exposes its internal matrices and a number of
-useful functions which we can readily use to interpret its operation. Let us
-start by generating a plot of the electron density using the method
-:meth:`pydft.DFT.get_density_at_points`.
-
-.. literalinclude:: scripts/01-electron-density.py
-    :language: python
-    :linenos:
-    :emphasize-lines: 25
-
-Running the above script yields the electron density.
-
-.. figure:: _static/img/user_interface/01-electron-density.png
-
-Using largely the same code, we can also readily build the electron density
-gradient magnitude using :meth:`pydft.DFT.get_gradient_at_points`.
-
-.. literalinclude:: scripts/02-electron-density-gradient.py
-    :language: python
-    :linenos:
-    :emphasize-lines: 25
-
-.. figure:: _static/img/user_interface/02-electron-density-gradient.png
+.. image:: _static/img/user_interface/06-grid-points.png

docs/exchange_correlation_functional_analysis.rst

@@ -13,13 +13,14 @@ calculations using Gaussian Type Orbitals.
 
 .. image:: _static/img/pydft_logo_full_512px.png
 
-:program:`PyDFT` currently supports LDA and PBE
-exchange-correlation functionals. The purpose of :program:`PyDFT` is mainly to
-serve as an educational tool to explain the inner workings of a DFT
-calculation. This program is not intended for professional calculations. It is
-not particularly fast nor offers a lot of features that more mature
-open-source of commercial packages offer. It does offer a unique insight into
-a working code and a considerable effort was made in documenting everything.
+The primary purpose of :program:`PyDFT` is to serve as an educational tool that
+illustrates the inner workings of a density-functional theory calculation.
+Currently, :program:`PyDFT` supports LDA and PBE exchange-correlation
+functionals. While it is not intended to replace mature open-source or
+commercial electronic-structure packages, care has been taken to achieve
+reasonable performance within the constraints of a Python implementation. In
+addition, a strong emphasis has been placed on code clarity and comprehensive
+documentation, providing detailed insight into a fully working DFT code.
 
 .. tip::
 
@@ -45,7 +46,7 @@ submitted via the `github issue tracker
    orbital_visualization
    becke_grid_analysis
    hartree_potential_analysis
-   exchange_correlation_functional_analysis
+   scalar_field_analysis
    benchmarks
    community_guidelines
 

docs/index.rst

@@ -0,0 +1,66 @@
+Scalar field analysis
+=====================
+
+.. contents:: Table of Contents
+    :depth: 3
+
+Once the electronic structure has been determined, a variety of scalar fields
+derived from the electron density can be analyzed and visualized. These fields
+provide insight into the spatial distribution of electronic properties and form
+the basis for interpreting exchange, correlation, and density-related
+quantities.
+
+Electron density and its gradient
+---------------------------------
+
+The :class:`pydft.DFT` class exposes its internal matrices and a number of
+useful functions which we can readily use to interpret its operation. Let us
+start by generating a plot of the electron density using the method
+:meth:`pydft.DFT.get_density_at_points`.
+
+.. literalinclude:: scripts/01-electron-density.py
+    :language: python
+    :linenos:
+    :emphasize-lines: 25
+
+Running the above script yields the electron density.
+
+.. figure:: _static/img/user_interface/01-electron-density.png
+
+Using largely the same code, we can also readily build the electron density
+gradient magnitude using :meth:`pydft.DFT.get_gradient_at_points`.
+
+.. literalinclude:: scripts/02-electron-density-gradient.py
+    :language: python
+    :linenos:
+    :emphasize-lines: 25
+
+.. figure:: _static/img/user_interface/02-electron-density-gradient.png
+
+Exchange potential
+------------------
+
+To construct the exchange potential at arbitrary grid points, we can use the
+script as shown below which uses the :meth:`pydft.MolecularGrid.get_exchange_potential_at_points`
+method.
+
+.. literalinclude:: scripts/08-exchange-potential.py
+	:language: python
+	:linenos:
+	:emphasize-lines: 13
+
+.. image:: _static/img/user_interface/08-exchange-potential.png
+
+Correlation potential
+---------------------
+
+In a similar fashion as for the exchange potential, we can use the method
+:meth:`pydft.MolecularGrid.get_correlation_potential_at_points` to obtain the
+correlation potential field.
+
+.. literalinclude:: scripts/08-correlation-potential.py
+	:language: python
+	:linenos:
+	:emphasize-lines: 13
+
+.. image:: _static/img/user_interface/08-correlation-potential.png