1Dstates of the beryllium atom: Quantum mechanical nonrelativistic calculations employing explicitly correlated Gaussian functions

Resonant two-photon spectroscopy of the 2s3d 1D2 level of neutral BeCook1, Vira2, Williams3 2020Phys. Rev. A7230View full textAdd to dashboardCite

“…[8] call for isotope shift measurements on neutral beryllium isotopes to confirm nuclear charge radii results obtained from spectroscopic measurements on the beryllium ion [9] in combination with the previously-measured 9 Be nuclear charge radius [10]. The absolute energy of the 2s3d 1 D 2 state, which is the focus of this work, was calculated by Sharkey et al using ECG, but not including relativistic or QED corrections, to be 64 418.17(5) cm −1 [11]. Since this calculation does not yet include higher-order corrections, it cannot be directly compared to our experimental result.…”

“…The results presented in this paper call for further improvement in the theoretical models. Sharkey et al calculated the absolute energy of the 2s3d 1 D 2 state, using ECG, but not including relativistic or QED corrections, to be 64 418.17(5) cm −1 [11]. The improved experimental value of 64 428.40321(55) cm −1 provides guidance for future calculations, including a test of QED if included in the calculation.…”

Singlet–triplet energy splitting between 1D and 3D (1s22snd), n= 3, 4, 5, and 6, Rydberg states of the beryllium atom (9Be) calculated with all-electron explicitly correlated Gaussian functions

“…In the present work the approach used in the calculations of the 1 D singlet states of 9 Be [1] is applied to calculate the energies of the lowest four triplet 3 D states of this atom. The lowest five 1 D beryllium states correspond to the following electronic configurations: (1s 2 2p 2 ) and (1s 2 2s nd), n = 3, 4, 5, and 6, while the lowest four 3 D states correspond to the configurations (1s 2 2s nd), n = 3, 4, 5, and 6 [2].…”

“…We have recently investigated the lowest five Rydberg 1 D states of the 9 Be isotope of the beryllium atom [1] with very accurate variational quantum mechanical calculations carried out with explicitly correlated Gaussian (ECG) functions [1]. 4200 ECGs were used for each state.…”

“…The Hamiltonian used in the calculations reported in Ref. [1] was obtained by rigorously separating out the kinetic energy of the motion of the center of mass from the laboratory-frame Hamiltonian. Thus it was explicitly dependent of the mass of the nucleus.…”