Modeling of the electron-molecule collision frequency variations in the undisturbed midlatitude D-region on the experimental basis

There are given and analyzed the main features of the model distribution of the height-temporal variations of the electron collisions with neutral molecules in the undisturbed midlatitude D-region of the ionosphere, obtained through long-time systematic experimental studies near Kharkov and episodic purposeful observation near Volgograd performed by the partial reflection and rocket methods.