H_2~+分子与共振相关的阈下谐波的取向效应

通过数值模拟的方法研究了H_2~+阈下谐波的取向效应.数值模拟过程中,主要关注波长为760nm的阈下谐波,通过逐次减去激发态贡献的方法,研究共振相关谐波不同取向角下的变化规律.结果表明:阈下平行、垂直谐波展示的复杂取向依赖与共振效应密切相关,该现象主要由与基态共振的各激发态的轴对称性导致.另外,用包含跃迁偶极子的简单模型对取向效应进行了概括描述,并以H_2~+第一激发态为演化初始态进行了验证.本文结果可为阈下谐波取向效应的实验研究提供参考.

Orientation Effects for Resonance-related Below-threshold Harmonics from H2 + Molecules

The orientation effect for Below-Threshold Harmonics (BTHs) from H2 + was studied through the numerical simulations.With excluding the contributions of excited states successively,the orientation dependence of BTHs,obtained with the driving laser wavelength of 760 nm,was analyzed in detail.The research results show that the complex orientation dependence of BTHs parallel and perpendicular to the laser polarization is closely related to the resonance effect between the ground state and the neighboring excited states,where the axis symmetry of these excited states play an important role.A simple model which contains the transition dipole is used to explain these complex orientation-related phenomena.The main results are checked with using the first excited state as the initial evolution state.The results can give suggestions on relevant experimental studies of orientation dependence of BTHs.