Ultralong-range Cs₂ Rydberg-ground molecules (nD _5/2 + 6S _1/2 F) (33 ≤ n ≤ 39, F = 3 or 4) are investigated by a two-photon photo-association spectroscopy of an ultracold Cs gas. Two vibrational ground molecular spectra of triplet ³ Σ and hyperfine mixed singlet-triplet ^1,3 Σ molecular states and their corresponding binding energies are attained. The experimental observations are simulated by an effective Hamiltonian including low energy electron scattering pseudopotentials, the spin-orbit interaction of the Rydberg atom, and the hyperfine interaction of the ground-state atom. The zero-energy singlet and triplet s-wave scattering lengths are extracted by comparing the experimental observations and calculations. Dependences of the measured binding energies on the effective principal quantum number, n _eff = n − δ_D (δ_D is the quantum defect of Rydberg D state), yield the scaling of , for deep triplet potential and , for shallow mixed singlet-triplet potential well. The simulations of low-energy Rydberg electron scattering show agreement well with the experimental measurements.

通过超冷 Cs 的双光子光结合光谱研究超长程 Cs ₂ Rydberg-ground 分子 ( nD _5/2 + 6 S _1/2 F ) (33 ≤ n ≤ 39, F = 3 或 4)气体。^三重态3 Σ和超精细混合单重态三重态^1,3 Σ的两个振动基分子光谱获得了分子状态及其相应的结合能。实验观察由有效哈密顿量模拟，包括低能电子散射赝势、里德堡原子的自旋轨道相互作用和基态原子的超精细相互作用。通过比较实验观察和计算，提取了零能量单重态和三重态 s 波散射长度。测量的结合能对有效主量子数的依赖性，n _eff = n - δ _D （δ _D 是里德堡D态的量子缺陷），对于深三重态势和,对于浅层混合单重态-三重态势阱。低能里德堡电子散射的模拟与实验测量结果吻合得很好。