Institut für Kernphysik, Goethe-Universität, Max-von-Laue-Strasse 1, D-60438 Frankfurt, Germany.
Nat Commun. 2012;3:1113. doi: 10.1038/ncomms2130.
Molecules show a much increased multiple ionization rate in a strong laser field as compared with atoms of similar ionization energy. A widely accepted model attributes this to the action of the joint fields of the adjacent ionic core and the laser on its neighbour inside the same molecule. The underlying physical picture for the enhanced ionization is that it is the up-field atom that gets ionized. However, this is still debated and remains unproven. Here we report an experimental verification of this long-standing prediction. This is accomplished by probing the two-site double ionization of ArXe, where the instantaneous field direction at the moment of electron release and the emission direction of the correlated ionizing centre are measured by detecting the recoil sum- and relative-momenta of the fragment ions. Our results unambiguously prove the intuitive picture of the enhanced multielectron dissociative ionization of molecules and clarify a long-standing controversy.
与具有相似电离能的原子相比，分子在强激光场中表现出更高的多次电离率。一个被广泛接受的模型将其归因于相邻离子核和激光对同一分子内其相邻原子的联合场的作用。增强电离的潜在物理图像是上向场原子被电离。然而，这仍然存在争议，并且尚未得到证实。在这里，我们通过探测 ArXe 的双位点双电离来报告这一长期预测的实验验证。这是通过检测碎片离子的反冲总和和相对动量来完成的，该实验测量了电子释放瞬间的瞬时场方向和相关电离中心的发射方向。我们的结果明确证明了分子增强的多电子离解电离的直观图像，并澄清了长期存在的争议。
