论文标题
核运动对谐振两个中心光电离的影响
Influence of nuclear motion on resonant two-center photoionization
论文作者
论文摘要
研究了原子在存在不同物种的相邻原子的情况下的光离子化。后者首先受到共鸣的光激发，从而导致双原子系统的自动化状态。之后，激发能通过两个中心螺旋钻过程无需传递到另一个原子，从而导致其电离。假设固定的核对内距离，从理论上讲，这种间接电离途径可以在直接光电离心上强烈主导。在这里，我们通过在Van-der-Waals分子中包括核运动来扩展谐振两中心光电离。分析公式的得出反映了分子振动动力学对两中心通道相对强度的影响。对于Li-He二聚体的具体示例，我们表明，两个中心的自动触发共振被核运动分为多重，而基于空间固定核的模型中，谐振线达到了直接光电离的相当增强水平。
Photoionization of an atom in the presence of a neighboring atom of different species is studied. The latter first undergoes resonant photoexcitation, leading to an autoionizing state of the diatomic system. Afterwards, the excitation energy is transferred radiationlessly via a two-center Auger process to the other atom, causing its ionization. Assuming a fixed internuclear distance, it has been predicted theoretically that this indirect ionization pathway can strongly dominate over the direct photoionization. Here, we extend the theory of resonant two-center photoionization by including the nuclear motion in van-der-Waals molecules. An analytical formula is derived reflecting the influence of molecular vibrational dynamics on the relative strength of the two-center channel. For the specific example of Li-He dimers we show that the two-center autoionizing resonances are split by the nuclear motion into multiplets, with the resonance lines reaching a comparable level of enhancement over direct photoionization as is obtained in a model based on spatially fixed nuclei.
