Some improvements to the description.

org/qmckl_ao.org

@@ -14,10 +14,10 @@ Gaussian ($p=2$):
  \exp \left( - \gamma_{ks} | \mathbf{r}-\mathbf{R}_A | ^p \right).
 \]
 
-In the case of Gaussian functions, $n_s$ is always zero.
-The normalization factor $\mathcal{N}_s$ ensures that all the functions
-of the shell are normalized to unity. Usually, basis sets are given
-a combination of normalized primitives, so the normalization
+In the case of Gaussian functions, $n_s$ is always zero.  The
+normalization factor $\mathcal{N}_s$ ensures that all the functions of
+the shell are normalized (integrate) to unity. Usually, basis sets are
+given a combination of normalized primitives, so the normalization
 coefficients of the primitives, $f_{ks}$, need also to be provided.
 
 Atomic orbitals (AOs) are defined as
@@ -26,10 +26,11 @@ Atomic orbitals (AOs) are defined as
 \chi_i (\mathbf{r}) = \mathcal{M}_i\, P_{\eta(i)}(\mathbf{r})\, R_{\theta(i)} (\mathbf{r})
 \]
 
-where $\theta(i)$ returns the shell on which the AO is expanded,
-and $\eta(i)$ denotes which angular function is chosen.
-Here, the parameter $\mathcal{M}_i$ is an extra parameter which allows
-the normalization of the different functions of the same shell to be
+where $\theta(i)$ returns the shell on which the AO is expanded, and
+$\eta(i)$ denotes which angular function is chosen and $P$ are the
+generating functions of the given angular momentum $\eta(i)$.  Here,
+the parameter $\mathcal{M}_i$ is an extra parameter which allows the
+normalization of the different functions of the same shell to be
 different, as in GAMESS for example.
 
 In this section we describe first how the basis set is stored in the