Absolute ionization and excitation rate coefficients have been evaluated for arbitrary excited states at certain electron temperatures kTe and electron densities Ne of the Lithium-like ions Ar XVI. The populations of 24 excited levels are calculated for the doublet state of the Li-like Ar ion. The calculations have been carried out by using the coupled rate simultaneous equations in which the monopole and quadruple transitions have been introduced in the calculations in addition to the dipole transitions. A theoretical population model has been developed to study the influence of the different processes that might contribute to the population of the different levels at the plasma parameters. The population densities of these different levels were then derived from these rate coefficients.