fix list-> np.array format

src/2_debye_model.md

@@ -102,8 +102,8 @@ where $x=\frac{\hbar\omega}{k_{\rm B}T}$ and $\Theta_{\rm D}\equiv\frac{\hbar\om
 
 ```python
 
-T = [1.35,2.,3.,4.,5.,6.,7.,8.,10.,12.,14.,16.,20.,28.56,36.16,47.09,55.88,65.19,74.56,83.91,103.14,124.2,144.38,166.78,190.17,205.3]
-c = [0.,0.,0.,0.,0.,0.,0.0719648,0.1075288,0.2100368,0.364008,0.573208,0.866088,1.648496,4.242576,7.07096,10.8784,13.47248,15.60632,17.27992,18.6188,20.33424,21.63128,22.46808,23.05384,23.47224,23.68144]
+T = np.array([1.35,2.,3.,4.,5.,6.,7.,8.,10.,12.,14.,16.,20.,28.56,36.16,47.09,55.88,65.19,74.56,83.91,103.14,124.2,144.38,166.78,190.17,205.3])
+c = np.array([0.,0.,0.,0.,0.,0.,0.0719648,0.1075288,0.2100368,0.364008,0.573208,0.866088,1.648496,4.242576,7.07096,10.8784,13.47248,15.60632,17.27992,18.6188,20.33424,21.63128,22.46808,23.05384,23.47224,23.68144])
 
 def c_einstein(T, T_E):
     x = T_E / T