The quantum mechanical effects are investigated on the half-life of α decay. To this aim the penetration probability in α decay of spherical isotopes of 146Sm, 148Sm, 148Gd, and 224Ra is calculated by employing coupled channel formalism by considering the effects of surface vibrations in the daughter nucleus; the obtained results are compared with those calculated by the semiclassical WKB approximation using two versions of the proximity potential. It is shown that by including low-lying excitation states the results are modified, in better agreement with experimental data.
