The width and life-time of the quasibound state of the α cluster in intense monochromatic electromagnetic (laser) field are discussed in details. The laser modified three dimensional potential barrier felt by the α particle is investigated analytically in long wave approximation and zero-order approximations with some different nuclear models: Coulomb potential with rectangular well, and with Woods–Saxon type potential. We show that the circularly polarized electromagnetic field and the special parameters of the nuclear potentials determine an enhancement of the decay probability, so the life-time of the quasibound state decreases in few times compared to the case of free field.

In this paper a wavefunction-centered description of decaying states that are coupled to an external potential of general time-dependence is investigated. We present the application of non-Hermitian spectral calculations merged with the (t,t')-formalism to estimate the possible time-dependent potential induced corrections to the lifetime of quasi-stationary states. The appliance of the formalism is demonstrated on some specific potential models as illustrative examples that represent decaying systems. We argue, that the presented framework and computational technique might provide a way to evaluate the lifetime of quasi-stationary states of different types of physical decaying systems that are subjected to perturbative, time-dependent drivings.