K2.

q6.1 Consider the Dirac 6 atom, i.e., the bound state to the potential oac5(:r). Suppose a perturbation is introduced in the form of a square well, H ' : V0 for M g g and zero elsewhere. (a) Calculate the rstorder energy correction E1 to the bound state. (b) Let Vb : Vc be the condition when E1 is equal to the unperturbed energy. If V0 2 Va, the perturbation is said to be strong; if V0