Table . The summary of calculated properties of RbBi2 and CsBi2 compared to experimental results (marked with label expt.). The density of states is given in units of eV -1 /f.u., both mean frequency 𝝎 and logarithmic frequency 𝝎 𝒍𝒏 in units of THz and critical temperatures in K. In a monoatomic case this integral corresponds to Hopfield parameter. The calculated value of the integral is 0.90 and 1.26 for RbBi2 and CsBi2, respectively. This suggests that, in addition to the lowering of frequency, the slight changes of the electronic structure resulting in lowering the Fermi velocity and increased DOS(EF) strengthen the EPC.