Theoretical [Cl II] line intensity ratio ﹩R_{1}=I﹩(﹩3s^{2}3p^{4}﹩ ¹D₂–﹩3s^{2}3p^{4}﹩ ¹S₀)﹩/I﹩(﹩3s^{2}3p^{4}﹩ ³P₂–﹩3s^{2}3p^{4}﹩ ¹D₂) ﹩=I﹩(6161.8 Å)﹩/I﹩(8578.7 Å), where I is in energy units plotted as a function of logarithmic electron temperature (﹩T_{e}﹩ in K) for several values of logarithmic electron density (﹩N_{e}﹩ in cm⁻³) in the range ﹩\mathrm{log}\,N_{e}=4.0{\mbox{--}} 7.0﹩. Values of ﹩R_{1}﹩ for ﹩N_{e}< 10^{4}﹩ cm⁻³ are coincident with those at ﹩N_{e}=10^{4}﹩ cm⁻³.