提出了一种新方法,精确确定了稀土Eu原子第一电离阈的位置.先用脉冲电场对Eu原子的高激发Rydberg态进行延时场电离探测,再通过反向静电场排除光电离和自电离等其他路径所产生的离子信号的干扰,观察并研究了Eu原子第一电离阈随着电场移动的规律.由此所确定的零场下第一电离阈的数值与采用其他方法所确定的文献值相一致,从而验证了该方法的可靠性.
In this paper,we present a new method to determine the first ionization limit of europium atom.Firstly,time delayed field ionization is used to detect highly excited Rydberg states of europium atom.Secondly,reversed static electric field is used to exclude ion signal from photoionization,autoionization and other path.The law of first ionization limit shift of europium atom in electric field is studied.First ionization limit in zero electric field is deduced from data of first ionization limit shift in electric field.This value is well coincident with the reported values deduced by other methods.