Akagi H, Otobe T, Staudte A, Shiner A, Turner F, Dörner R, Villeneuve D M, Corkum P B
Joint Laboratory for Attosecond Science, University of Ottawa and National Research Council, 100 Sussex Drive, Ottawa, Ontario K1A 0R6, Canada.
Science. 2009 Sep 11;325(5946):1364-7. doi: 10.1126/science.1175253.
Tunneling, one of the most striking manifestations of quantum mechanics, influences the electronic structure of many molecules and solids and is responsible for radioactive decay. Much of the interaction of intense light pulses with matter commences with electrons tunneling from atoms or molecules to the continuum. Until recently, this starting point was assumed to be the highest occupied orbital of a given system. We have now observed tunneling from a lower-lying state in hydrogen chloride (HCl). Analyzing two independent experimental observables allowed us to isolate (via fragment ions), identify (via molecular frame photoelectron angular distributions), and, with the help of ab initio simulations, quantify the contribution of lower-lying orbitals to the total and angle-dependent tunneling current of the molecule. Our results bolster the emerging tenet that the coherent interaction between different orbitals--which can amplify the impact of lower orbitals--must be considered in tunneling processes.
隧穿是量子力学最显著的表现之一，它影响着许多分子和固体的电子结构，并导致放射性衰变。强光脉冲与物质的许多相互作用始于电子从原子或分子隧穿到连续介质。直到最近，人们还认为这个起始点是给定系统的最高占据轨道。我们现在观察到了氯化氢（HCl）中较低能态的隧穿。分析两个独立的实验可观测量使我们能够（通过碎片离子）分离、（通过分子框架光电子角分布）识别，并借助从头算模拟量化较低能态轨道对分子总隧穿电流和角度相关隧穿电流的贡献。我们的结果支持了一个新出现的原则，即在隧穿过程中必须考虑不同轨道之间的相干相互作用，这种相互作用可以放大较低轨道的影响。
