A successful example of potential energy landscape of the proton-rich alpha
-emitter Te-106, showing for the first time the valley corresponding to alp
ha-decay, is presented. A phenomenological shell correction has been added
to the macroscopical (liquid-drop) Yukawa-plus-exponential deformation ener
gy. The difficulties to produce such a valley are analysed on a potential e
nergy surface of Pu-236.