The recovering procedure of the electron–phonon interaction (EPI) functions from the additional nonlinearities of the current-voltage curve (I−V curve) of point contacts associated with an excess current is considered. The approach proposed takes into account both inelastic scattering, which causes suppression of the excess current in the reabsorption of nonequilibrium phonons by electrons undergoing Andreev reflection (Andreev electrons), and elastic processes associated with the electron–phonon renormalization of the energy spectrum in a superconductor. The results obtained are systematically expounded for both the ballistic contacts, wherein the second derivatives of the I−V curve in the normal state are proportional to the EPI functions, and inhomogeneous contacts (with dirty constrictions and clean banks), whose second derivatives in the normal state are either free of phonon singularities or weakly pronounced.

考虑了与过电流相关的点接触的电流 - 电压曲线（ I - V曲线）的附加非线性的电子 - 声子相互作用（EPI）函数的恢复过程。所提出的方法既考虑了非弹性散射，也考虑了非弹性散射，这会抑制经历安德烈夫反射的电子（安德烈夫电子）对非平衡声子的重吸收过程中的过量电流，以及与超导体中能谱的电子-声子重整化相关的弹性过程. 系统地阐述了两种弹道接触所获得的结果，其中I - V的二阶导数正常状态下的曲线与 EPI 函数和非均匀接触（带有脏收缩和干净的堤岸）成正比，其正常状态下的二阶导数要么没有声子奇点，要么不明显。