分子谐波辐射中的非绝热效应

Nonadiabatic Effects in Molecular High Order Harmonic Generation

理论研究了在非伯恩奥本海默近似下H2+高次谐波辐射中的非绝热现象。结果表明,由于谐波辐射在激光上升以及下降区间的不对称性,谐波光谱呈现红移现象。但是谐波红移会随着激光强度和激光脉宽的增大而减弱。由于电子与核耦合的作用,谐波光谱在较大核间距离处呈现非奇次谐波,并且其强度会随着激光强度和激光脉宽的增大而增强。随着H2+分子轴与激光偏振角的增大,谐波红移以及非奇次谐波的产生都被减弱。

The nonadiabatic effects in the molecular high-order harmonic generation(MHHG)from H2+have been theoretically investigated by using the Non-Bohn-Oppenheimer approximations.The results show that due to the asymmetric contributions of the harmonic emission on the rising and the falling parts of the laser field,the frequency red-shifts in the MHHG can be found.However,the red-shifts of the harmonics can be decreased with the increase of the pulse intensity and the pulse duration.Due to the coupling of the electron-nuclear dynamics,the non-odd harmonics can be produced at the larger internuclear distance.Moreover,the signals of the non-odd harmonics can be enhanced with the increase of the pulse intensity and the pulse duration.With the increase of the alignment angle of the molecule ions,the red-shifts of the harmonics and the generations of the non-odd harmonics are both decreased.