  We estimate the contribution of the long-wavelength el-TO-ph interaction and
discuss the effect it has on electron pairing in doped polar systems like
SrTiO3 and PbTe. The analytical and numerical results presented in the study
indicate that the el-TO-ph interaction tends to contribute little to the total
strength of electron-phonon coupling in these and related materials. To explain
this fact we consider possible reasons why the effect of the polar
long-wavelength transverse optical phonons on the coupling constant "lambda" is
far less than one might suppose.
