Electrical and optical dipole polarizabilities of two lowest triplet states of the beryllium atom

High-accuracy static and dynamic polarizabilities of the $2^3{P}_u$ and ${}^3{S}_g$ states of the neutral beryllium atom are reported. The calculations employed explicitly correlated Gaussian (ECG) basis sets, and first-order wave functions were obtained by minimization of the Hylleraas functional. The final basis sets used for the response-property calculations contained c.a. 7000-8000 functions, depending on the polarizability component and the chosen symmetry. The results cover frequencies from the static limit, $\omega =0$, up to the third resonance for the $2^3{P}_u$ state and up to the second resonance for the $3^3{S}_g$ state. To the best of our knowledge, these are the first calculations of dynamic and static polarizabilities for these excited states of the beryllium atom using explicitly correlated basis sets.