We utilize the Sturmian expansion of the Dirac-Coulomb Green function [R. Szmytkowski, J. Phys. B 30, 825 (1997)] to obtain components of the dynamic dipole polarizability tensor of the relativistic hydrogenlike atom in the ground state. It is found that the tensor may be expressed in terms of two independent quantities: a scalar polarizability and a vector polarizability, the latter being of the relativistic origin. In the static and nonrelativistic limits the previously known expressions for the scalar polarizability are recovered.

• Received 25 May 2001

DOI:https://doi.org/10.1103/PhysRevA.65.012503