Energy levels, transition probabilities and effective collision strength for 1s² 2s² 2p⁶ 3l, 4l, 5l (l = 0, 1, 2, 3, 4) states of sodium like Fe are used in the determination of the reduced populations for 21 fine structure levels over a wide rang of electron density values (10¹⁸ to 10²⁰ cm^–3) and at against electron plasma temperatures. Gain coefficients are evaluated and plotted against the electron density.