Theoretical study of the NaLi molecule: potential energy curves, spectroscopic constants, dipole moments and radiative lifetimes

Abstract

The adiabatic potential energy curves and the permanent and transition dipole moments of the low-lying electronic states of the NaLi molecule dissociating into Na(3s, 3p, 4s, 3d, 4p) + Li(2s, 2p, 3s, 3p, 3d) have been investigated. The molecular calculations are performed using an ab initio approach based on non-empirical pseudopotentials for Na+ and Li+ cores, parameterized l-dependent polarization potentials and full configuration interaction calculations through the CIPCI quantum chemistry package. The derived spectroscopic constants of the ground state and lower excited states are in good agreement with available experimental and theoretical works. However, the 7–101,3Σ+, 5–71Π, 2–63Π and 1–31,3Δ excited states are studied for the first time. The permanent dipole moment of NaLi has revealed both ionic characters relating to electron transfer and yielding Na+Li− and Na−Li+ arrangements. The transition dipole moment is used to evaluate the radiative lifetimes of the vibrational levels trapped in the 21Σ+ excited state for the first time. In addition to the bound–bound contribution, the bound-free term has been evaluated exactly using the Franck–Condon (FC) approximation and added to the total radiative lifetime.

Theoretical investigation of the low-lying electronic states of the alkaline hydride BeH2+ ion: Potential energy curves, spectroscopic constants, vibrational levels, and transition dipole functions

“…It is the aim of this paper to determine accurate potential energy curves for 2 Σ + , 2 Π, and 2 Δ symmetries of the alkaline hydride BeH 2+ ion dissociating into Be + (2s, 2p, 3s, 3p, 3d, 4s, 4p, and 4d) + H + and Be 2+ + H(1s and n = 2).Their spectroscopic constants, the vibrational energy level spacing for the bound electronic states and the transition dipole functions from X 2 Σ + and 2 2 Σ + to higher excited states of 2 Σ + and 2 Π symmetries will be performed. We extend in this work our ab initio results obtained on molecular states of many ionic and neutral diatomic systems such as BeH + [17], BeLi + [18], BeLi 2+ [19], LiH [20], LiNa [21], CsLi [22], LiH + [23], LiNa + [24], LiK + [25], NaK + [26,27], KRb + [28], [29], [30], CsLi + and CsNa + [31].…”

“…METHOD OF CALCULATIONS As in our previous works on XY + ionic systems (X and Y = H, Li, Na, K, Rb, and Cs) [23][24][25][26][27][28][29][30][31], the Li 2 + K 2 + alkaline hydride BeH 2+ ion is treated as a one electron system using the non empirical pseudopotential of Barthelat and Durand [32] in its semi local form and used in many previous works [17][18][19][20][21][22][23][24][25][26][27][28][29][30][31]. For the simula tion of the interaction between the polarizable Be 2+ core with the valence electrons and the hydrogen nucleus, a core polarization potential V CPP is used, according to the operator formulation of Müller, Flesh and Meyer [33]:…”

Ab initiostudy of permanent electric dipole moment and radiative lifetimes of alkaline-earth-metal--Li molecules

“…Due to the large PDM of bi-alkali-metal polar molecules (KRb [8,9], NaLi [10], NaCs [11], RbLi [12], RbCs [13,14], CsLi [15,16]), previous studies on dipoledipole interactions and electric-field control in the ultracold regime were primarily centered around bi-alkali-metal polar molecules. Alkali-metal-Li molecules, such as NaLi [10], RbLi [12], and CsLi [15,16], have already been cooled to temperatures in the ultracold regime and have been produced in their electronic ground states through photoassociation [17] and Feshbach resonance [18] techniques. However, in order to manipulate molecules to achieve quantum degeneracy in the absolute ground state, molecules should be localized in a single quantum state, defined by their vibrational, rotational, and hyperfine structure.…”

Particle—hole bound states of dipolar molecules in an optical lattice

“…The molecule prepared in the ground state has a permanent electric moment d = 0.58D [45]. With a lattice constant a ∼ 0.5µm, a s /a ∼ 0.01 and the transversal tapping frequency ω ⊥ ∼ 2π × 10 4 Hz, we have t ∼ 1nK, U 1D ∼ 25nK and U 2D ∼ 50nK.…”