Thermally activated hopping of two ions trapped in a bistable potential well
Thermally activated hopping of two ions trapped in a bistable potential well
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DOI：
10.1088/1464-4266/6/3/004
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发表时间：
2004-03-01
期刊：
影响因子：
--
通讯作者：
Toschek, PE
中科院分区：
文献类型：
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作者：
Abich, K;Keil, A;Toschek, PE
当两个离子处于球状保罗陷阱中时，谐波捕获电势通过库仑斥力变成双稳态阱。空间分辨光电倍增管或增感 CCD 相机通过激光激发的共振散射对两个 Ba 离子进行限制、激光冷却和观察。再泵浦激光器将离子从亚稳态释放。发现局部冷却良好的离子。当激光失谐时，拉曼冷却速率和离子温度会发生变化。发生从结晶态到环形气体的转变。当离子 (i) 被激发到非荧光亚稳态，或 (ii) 属于另一种同位素种类时，离子就会被区分。在高热激发下发现跳跃率为 1 s(-1)。在其他地方，速率下降了两个数量级，并且随着势能/动能 = 15 附近的温度共振变化，其中亮离子在激光束上游跳跃的可能性是下游的五倍。陷阱中的两个可辨别的离子代表了用于研究反应动力学的微观模型系统。
With two ions in a spheroidal Paul trap, the harmonic trapping potential turns, by Coulomb repulsion, into a bistable well. Two Ba ions have been confined, laser-cooled, and observed, via their laser-excited resonance scattering, by a spatially resolving photomultiplier, or intensifying CCD camera. A repump laser releases the ions from a metastable state. Well-cooled ions are found localized. When the laser is detuned, the Raman cooling rate and the ions' temperature vary. A transition from the crystallized state to a toroidal gas takes place.The ions are discriminated when one (i) gets excited into a non-fluorescing metastable state, or (ii) is of another isotopic species. Hopping rates of 1 s(-1) are found at high thermal excitation. Elsewhere, the rates drop by two orders of magnitude, and vary resonantly with temperature near potential energy/kinetic energy = 15, where the bright ion's hopping upstream of the laser beam is five times more likely than downstream.Two discernible ions in a trap represent a microscopic model system for the study of reaction kinetics.