Positronium in a Liquid Phase: Formation, Bubble State and Chemical Reactions

Figure 15

Pick-off annihilation rate constant of Ps, localized in a bubble of 𝑅 when 𝑉⁺₀+𝑉⁻₀=0 (brown curve). For small 𝑅 (≲2.3Å) the calculated values of 𝜆_po are equal to 𝜆₊. The red line shows the pick-off annihilation rate constant, calculated according to the Tao-Eldrup formula. The dashed line is the calculation according to the finite potential well model (for comparison we adopted that the depth of the well is (1−1/𝜀²)Ry/2≈5.1eV and its radius is 𝑅; in this case the minimal radius of the well when there appears an energy level for Ps is 𝛿_𝑈=0.96Å).