WKB approach to calculating the lifetime of quasistationary states

A novel WKB approach to calculating the lifetime of quasistationary states in the potential wells of the form V(x) = P(x) - mu Q(x), where P(x) is the radial part of the potential for the spherically symmetric harmonic oscill ator or the hydrogen atom and Q(x) isa polynomial, is suggested. In this ap proach, the usual explicit procedure of the asymptotic matching of the pert urbative and WKB wave functions is avoided and a simple formula for the ima ginary part of the energy is found. The leading and the first correction te rms for the imaginary part of the energy and the related Lifetime are analy tically calculated.