Enhanced Resonant Positron Annihilation due to Nonfundamental Modes in Molecules
Enhanced Resonant Positron Annihilation due to Nonfundamental Modes in Molecules
复制标题
由于分子中的非基本模式而增强的共振正电子湮灭
DOI：
10.1103/physrevlett.125.173401
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发表时间：
2020
影响因子：
8.6
通讯作者：
Surko, C. M.
中科院分区：
文献类型：
--
作者：
Ghosh, S.;Danielson, J. R.;Surko, C. M.
正电子通过基本振动模式的费什巴赫共振激发附着在大多数分子上，这导致湮灭率大大提高。除了最小的分子外，振动能量转移进一步提高了这些湮灭速率。有证据表明，在烷烃和环烷烃分子中，这可以通过激发除基本振动以外的其他振动而发生，并产生大致相当的湮灭速率。这些特征与红外吸收光谱进行了比较。讨论了一种可能的机制，涉及组合和泛音振动。
Positrons attach to most molecules through Feshbach resonant excitation of fundamental vibrational modes, and this leads to greatly enhanced annihilation rates. In all but the smallest molecules, vibrational energy transfer further enhances these annihilation rates. Evidence is presented that in alkane and cycloalkane molecules, this can occur by the excitation of other than fundamental vibrations and produce roughly comparable annihilation rates. These features are compared to infrared absorption spectra. A possible mechanism is discussed that involves combination and overtone vibrations.