Keywords: 
• 长程铯里德堡分子 /
• 电子-原子散射 /
• 势能曲线

Abstract: Rydberg atom, with a large principal quantum number n, has big size, long lifetime, strong long-range interactions, and so on. These properties make Rydberg atoms potential candidate of quantum gate and single-photon source. Ryd-berg electron can interact with nearby ground-state atom, which is polarized by the Rydberg electron and is bound to the orbit of Rydberg electrons forming Rydberg molecule. As the kinetic energy of the Rydberg electron is very low, only the lowest partial waves will contribute to the molecular potential.
In this paper, the low electron-atom scattering with the semi-classical approximation is introduced, and the pseu-dopotential of interaction between Rydberg electron and ground-state atom is used to describe the long-range Rydberg molecular potential. Molecular potential curves for cesium (nS, n=30–60) are plotted according to the results of nu-merical computation, from which the outermost potential depth De and the equilibrium distance r0 of long-range cesium Rydberg molecule are deduced. Potential curves of cesium Rydberg molecules are consistent with the distribution curves in radial probability densities of cesium Rydberg electrons. Dependences of De and r0 on the principal quantum number n are investigated, this has an important role for the experimental measurements. The size of a Rydberg molecule depends on the equilibrium distance r0 and is proportional to the square of effective principal quantum number (n?δ)2. The calculated outermost potential depth De of Rydberg molecule becomes smaller with the increase of principal quan-tum number n. Rydberg molecule is very sensitive to the external field and can be used to measure and monitor weak signals.