Polarizability and electric field gradient of two-electron quantum dots

The energy levels of the quantum dots are evaluated by using Quantum Genetic Algorithm procedure and Hartree-Fock Roothaan method. Based on the calculated energies and wave functions, static dipole polarizability, oscillator strength and electric field gradient of helium/helium-like quantum dots are calculated as a perturbative calculation. It is worth to note that impurity charge and dot radius have a strong effect on the dipole polarizability, the oscillator strength and the electric field gradient. In small dot radii, since the spatial confinement effect is dominant, the polarizability of system is very weak. The polarizability increases monotonically with the increase of dot radius and then reaches a saturation value in large dot radii. On the other hand, the electric field gradient increases as dot radius decreases.