diff --git a/examples/test_morse.py b/examples/test_morse.py
index 6de9119..227203c 100644
--- a/examples/test_morse.py
+++ b/examples/test_morse.py
@@ -180,8 +180,8 @@ def run_krc_morse_potential(energy, index, num_samples=10000, run_sim=True):
 R_E_2 = np.zeros(num_energies)
 
 for index, energy in enumerate(energies):
-    R_N[index], R_E[index] = run_krc_morse_potential(energy, index, num_samples=num_samples, run_sim=False)
-    R_N_2[index], R_E_2[index] = run_morse_potential(energy, index, num_samples=num_samples, run_sim=False)
+    R_N[index], R_E[index] = run_krc_morse_potential(energy, index, num_samples=num_samples, run_sim=True)
+    R_N_2[index], R_E_2[index] = run_morse_potential(energy, index, num_samples=num_samples, run_sim=True)
 
 plt.semilogx(energies, R_N, label='R_N Morse-Kr-C H-Ni, Es=1.5eV', color='purple')
 plt.semilogx(energies, R_N_2, label='R_N Morse H-Ni, Es=1.5eV', color='green')
diff --git a/src/geometry.rs b/src/geometry.rs
index 8e3d31a..a915629 100644
--- a/src/geometry.rs
+++ b/src/geometry.rs
@@ -66,6 +66,7 @@ impl Geometry for Mesh0D {
         let electronic_stopping_correction_factor = input.electronic_stopping_correction_factor;
 
         let densities: Vec<f64> = input.densities.iter().map(|element| element/(length_unit).powi(3)).collect();
+        assert!(densities.len() > 0, "Input Error: density list empty.");
 
         let total_density: f64 = densities.iter().sum();
 
@@ -135,6 +136,7 @@ impl Geometry for Mesh1D {
 
         let layer_thicknesses = geometry_input.layer_thicknesses.clone();
         let electronic_stopping_correction_factors = geometry_input.electronic_stopping_correction_factors.clone();
+        assert!(electronic_stopping_correction_factors.len() > 0, "Input Error: Electronic stopping correction factor list empty.");
         let n = layer_thicknesses.len();
 
         let mut layers: Vec<Layer1D> =  Vec::with_capacity(n);
@@ -433,7 +435,7 @@ impl Geometry for Mesh2D {
 
         let simulation_boundary_points = geometry_input.simulation_boundary_points.clone();
         let electronic_stopping_correction_factors = geometry_input.electronic_stopping_correction_factors.clone();
-
+        assert!(electronic_stopping_correction_factors.len() > 0, "Input Error: Electronic stopping correction factor list empty.");
         let n = triangles.len();
 
         let mut cells: Vec<Cell2D> =  Vec::with_capacity(n);