School of Physics and Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology, Wuhan 430074, China.
Laboratory of Optical Information Technology, Wuhan Institute of Technology, Wuhan 430205, China.
Sci Rep. 2017 Feb 20;7:42585. doi: 10.1038/srep42585.
The partition of the photon energy into the subsystems of molecules determines many photon-induced chemical and physical dynamics in laser-molecule interactions. The electron-nuclear energy sharing from multiphoton ionization of molecules has been used to uncover the correlated dynamics of the electron and fragments. However, most previous studies focus on symmetric molecules. Here we study the electron-nuclear energy sharing in strong-field photoionization of HeH by solving the one-dimensional time-dependent Schrödinger equation (TDSE). Compared with symmetric molecules, the joint electron-nuclear energy spectrum (JES) of HeH reveals an anomalous energy shift at certain nuclear energies, while it disappears at higher and lower nuclear energies. Through tracing the time evolution of the wavepacket of bound states, we identify that this energy shift originates from the joint effect of the Stark shift, associated with the permanent dipole, and the Autler-Townes effect due to the coupling of the 2pσ and 2sσ states in strong fields. The energy shift in the JES appears at certain nuclear distances only when both Stark effect and Autler-Townes effect play important roles. We further demonstrate that the electron-nuclei energy sharing can be controlled by varying laser intensity for asymmetric molecules, providing alternative approaches to manipulate photochemical reactions for more complex molecules.
光子能量在分子子系统中的分配决定了激光与分子相互作用中许多光子诱导的化学和物理动力学。多光子电离分子的电子-核能量共享已被用于揭示电子和碎片的相关动力学。然而，大多数先前的研究都集中在对称分子上。在这里，我们通过求解一维含时薛定谔方程（TDSE）研究了 HeH 强场光电离中的电子-核能量共享。与对称分子相比，HeH 的联合电子-核能谱（JES）在某些核能处显示出异常的能量移动，而在更高和更低的核能处则消失。通过跟踪束缚态波包的时间演化，我们确定这种能量移动源自于与永久偶极相关的斯塔克移动和由于在强场中 2pσ 和 2sσ 态的耦合而产生的奥特-汤斯效应的联合效应。只有当斯塔克效应和奥特-汤斯效应都起重要作用时，JES 中的能量移动才会出现在某些核距离处。我们进一步证明，通过改变激光强度可以控制不对称分子的电子-核能量共享，为更复杂分子的光化学反应提供了替代的操纵方法。
