Samuel, Sitotaw2018-07-032023-11-092018-07-032023-11-091989-06http://10.90.10.223:4000/handle/123456789/5826'l'he electf.'on ··phonon interaction bar; ed on the harm::>nic approx.imati.on for phonons is discussed by considering several physical. models. Some consequences of t.his interaction I such as the possibility of cooper pairing and the BCS theory of superconductiv:lty are described. T\'IO proposed mechanisms of High-T c superconductivity both based on the electron-ion interaction of electron pairing are discussed. II 2D BCS model results the observed values of Tand the absence of the isotope effect in its conventional c form. Another model based on the non harmonic double-well potentials in the cu-o chain in YBCO is also studied. A qualitative prediction of the effect of pressure on Tc and the smallness of the critical current is madeenElectron –Phonon InteracitionsThesis