A phenomenological model describing the temperature dependence of the positronium yields ( I Ps , %) was tested in pure liquids of different polarity. The investigated solvents were: m-xylene (m-Xy) and iso -octane (i-C8) as aromatic and aliphatic nonpolar hydrocarbons, methanol (MeOH), water and dimethyl formamide as polar solvents with and without OH group. Arrhenius type linear relationship predicted by the model for the ln Q vs 1/ T function, where Q =(100/ I Ps −1), was found to be valid in all cases. The slopes of the lines correspond to the activation energy differences (Δ E * = E rec − E Ps ) between the two main competing reaction pathways in the positron spur, i.e., solvent recombination (e − + M + ) and positronium formation (e − + e + ). The slopes were positive, i.e., Δ E * <0 and E rec < E Ps . For polar liquids, correlation seems to exists between Δ E * and the electron mobility ( μ ) or the activation energy of the viscosity ( E η ).