Dynamic and geometric alignment of molecules induced by intense laser fields

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• 作者：Hongchun Wu ; Jianxin Chen ; Xingshan Jiang ; Bomin Huang ; Shuangmu Zhuo
• 关键词：Dynamic and geometric alignment ; Molecule ; Intense femtosecond laser field
• 刊名：Optik - International Journal for Light and Electron Optics
• 出版年：2008
• 出版时间：December 2008
• 年：2008
• 卷：119
• 期：16
• 页码：777-782
• 全文大小：186 K

文摘

We present a method to discuss simultaneously the relative importance of molecular dynamic and geometric alignment induced by intense laser fields in theoretical view. This method divides the process of molecular alignment into three steps, which are tightly correlated with that of molecular multielectron dissociative ionization and Coulomb explosion. A fourth-order Runge-Kutta algorithm and a developed counting approach are used to calculate the angular distribution of molecules in the first and second steps of molecular alignment. The last step is described by a field-ionization, Coulomb explosion model. The angular distribution of molecules at the critical distance originated from geometric alignment is obtained by calculating the volume of shells associated with a series of particular angle. The final angular distributions of molecules are obtained by properly weighting the results of three steps. The numerical results of distinguishing between dynamic and geometric alignment for certain conditions are presented and discussed. Our computational results show that the alignment mechanism, which dominates the observed anisotropy of angular distributions of ionic fragments for a given condition, is determined by the dependences of the extent of dynamic and geometric alignment on laser parameters and molecular parameters.