The Ultrafast Structural Dynamics of Ammonia Cation Following Strong-Field Ionization
DOI:
https://doi.org/10.29070/crs12f10Keywords:
Ammonia Cation, Strong-Field Ionization, Ultrafast Structural Dynamics, Fourier Transform, Polyatomic MoleculesAbstract
This work examines rapidly changing structural dynamics of ammonia cation (Nha+) after strong field ionization by use of Fourier transform laser-induced electron diffraction (FT-LIED). Through the analysis of high-energy electrons backscatter in the rescattering regime, molecular interference signals were obtained and converted to extract real-space structural information without using theoretical fitting models. The outcome of the results shows that the internuclear distances are .31 + 0.03 A (N–H) and 2.24 + 0.03 A (H–H), which result in H - N - H bond angle of 117 + 5degree. Complementary quantum chemistry simulations show the strong laser field has a significant effect on the potential energy surface due to which is a field-dressed structure that is consistent with experimental measurements. These results demonstrate that FT-LIED is capable of probing the geometry of molecules directly in the femtosecond time range and can give information regarding the contribution of strong-field effects to the mechanisms of structural changes in polyatomic molecules.
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