State Key Laboratory for Mesoscopic Physics, Department of Physics, Peking University, Beijing 100871, People's Republic of China.
J Phys Chem A. 2010 Jul 1;114(25):6751-6. doi: 10.1021/jp1018197.
In intense femtosecond laser fields, molecules could be tunnel ionized from multiple valence orbitals, which produces molecular ions in different electronic states. In this article, we have used a reaction microscope to study double ionization of nitrogen by intense femtosecond laser pulses. It is found that some doubly charged molecular ions N(2)(2+) are metastable while others dissociate through charge symmetric dissociation (N(2)(2+) --> N(+) + N(+)) or charge asymmetric dissociation (N(2)(2+) --> N(2+) + N). The kinetic energy releases and angular distributions of atomic ions are measured for the dissociation channels. With the aid of the CASSCF and MRCI calculations, the electronic states are identified and the contributions of the valence orbitals are discussed for these dissociated molecular dications.
在高强度飞秒激光场中，分子可以从多个价轨道隧穿电离，从而产生处于不同电子态的分子离子。在本文中，我们使用反应显微镜研究了高强度飞秒激光脉冲对氮气的双电离。结果发现，一些双电荷分子离子 N(2)(2+) 处于亚稳态，而另一些则通过对称电荷解离（N(2)(2+) --> N(+) + N(+))或不对称电荷解离（N(2)(2+) --> N(2+) + N）解离。我们测量了这些解离分子双阳离子的离解通道的动能释放和离子角度分布。借助 CASSCF 和 MRCI 计算，我们确定了电子态，并讨论了这些离解的双阳离子中价轨道的贡献。
