Clean memory after writing formatted configuration

src/libnptm/Configuration.cpp

@@ -1067,6 +1067,12 @@ void ScattererConfiguration::write_formatted(string file_name) {
 					       );
       break;
     }
+    // Clean memory
+    delete[] xi_vec;
+    delete[] pu_vec;
+    delete[] ev_vec;
+    delete[] wn_vec;
+    delete[] wl_vec;
   } else { // idfc < 0, Dielectric functions are at XIP and XI is scale for dimensions
     double pu, wn;
     xi_vec = scale_vec;