Electric quadrupole moment of a hydrogen-like ion in s and p1/2 states

Relativistic formulas for the electric quadrupole moment of a hydrogen-like atom, induced by the hyperfine interaction, are derived for ns and np1/2 states. Both the magnetic dipole and electric quadrupole hyperfine interactions are taken into account. The formulas are valid for ions with arbitrary nuclear charge and spin. The induced quadrupole moment is compared with the nuclear quadrupole moment for a wide range of hydrogen-like ions.