Comment on “The Polarizability of a confined atomic system: an application of the Dalgarno-Lewis method”


 In a recent paper (2021 Eur. J. Phys. 42 045407), Antão and Peres study both the static and dynamic polarizability of a bound system. The binding potential they consider is the one-dimensional Dirac delta. The authors use the Dalgarno and Lewis method to calculate the polarizabilities to demonstrate its effectiveness in perturbation calculations. The authors left out essential steps in applying the time-dependent perturbation method to derive the expression for the dynamic electric polarizability. In addition, references which are useful to the paper are missing. To aid our comment, we first give a summary of the Dalgarno and Lewis method. Second, we present the work of the authors in deriving the dynamic electric polarizability. We follow by presenting the time dependent perturbation method, which is needed to derive the expression for the dynamic electric polarizability. In the process, we will provide some essential references, which will be of value to the subject of the paper.