分子取向对H2+谐波分布的影响

Alignment angle dependence of H2+ on spatial distribution of harmonic emission

摘要:

理论研究了H2+分子取向对谐波空间分布的影响. 结果表明：当激光偏振方向与分子轴方向一致时, 谐波辐射满足激光场正向时, 负向H核谐波辐射强度大于正向H核；激光场反向时, 正向H核谐波辐射强度大于负向H核. 随着分子取向角增大, 谐波辐射强度减弱, 尤其正向H核对谐波辐射的贡献明显减小, 因此导致正负向H核的谐波辐射强度差逐渐增大. 最后, 通过研究谐波辐射的时频分析以及电子波包随时间的演化给出了电子在双H核之间运动以及谐波空间分布的原因.

Abstract:

The alignment angle dependence of H2+ on the spatial distribution of the molecular high-order harmonic generation (MHHG) has been theoretically investigated. The result shows that when the laser polarization direction coincides with the molecular axis, the harmonic emission follows the rules. When the laser field is larger than zero, the MHHG from the negative-H is higher than that from the positive-H; while when the laser field is smaller than zero, the MHHG from the positive-H is higher than that from the negative-H. As the alignment angle of H2+ increases, the intensities of the harmonic spectra decreases. Especially for the case of the harmonic emission from the positive-H, a faster decrease of the harmonics can be found, thus leading to the enhanced intensity difference of the harmonics from the two-H nuclei. Finally, through studying the time-frequency analyses of the MHHG and the time-dependent electronic wave functions, the reasons behind the electron motion and the spatial distribution of the MHHG from the two-H nuclei are shown and discussed.