Merge branch 'master' into local

src/1_einstein_model.md

@@ -305,13 +305,13 @@ ax.set_yticks([1])
 ax.set_yticklabels(['$k_B$'])
 pyplot.hlines([1], 0, 1.5, linestyles='dashed')
 draw_classic_axes(ax)
-ax.text(1.01, 0.5, r'$k_{\rm B}T = \hbar \omega$', ha='left', color='r');
+ax.text(1.01, 0.5, r'$T= T_E= \hbar \omega_0/k_{\rm B}$', ha='left', color='r');
 ```
 
 The dashed line is the classical value, $k_{\rm B}$.
 Shaded area $=\frac{1}{2}\hbar\omega_0$, the zero point energy that cannot be removed through cooling.
 
-This is for just one atom. In order to obtain the heat capacity of a full material, we would have to multiply $C$ (or $\langle E \rangle$) by $3N$, _i.e._ the number of harmonic oscillators according to Einstein model.
+This is for just one atom. In order to obtain the heat capacity of a full material, we would have to multiply $C$ (or $\langle E \rangle$) by $3N$, _i.e._ the number of harmonic oscillators according to Einstein model. The plot below shows a fit of the Einstein model to the experimental data for the heat capacity of diamond.
 
 ```python
 fit = curve_fit(c_einstein, T, c, 1000)