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强场层析成像通过强场驱动的电子再散射实现取向分子的结构成像, 其优势在于无需预先计算不同原子的散射截面. 强场层析成像已成功应用于同核双原子分子结构的提取, 但对于更为普遍的异核分子体系, 其电子散射截面更为复杂, 该成像方案的适用性仍需进一步研究. 本文以异核双原子分子为例, 基于强场层析成像方案开展分子结构成像研究. 通过求解含时薛定谔方程, 获得光电子产量随分子轴取向角的变化, 并发展了一种异核分子散射截面随取向角变化的拟合方法. 通过拟合, 成功提取了分子核间距信息, 拟合结果与预设的分子核间距相一致. 研究结果表明, 强场层析成像方案同样适用于异核分子结构信息的提取, 为复杂分子体系的结构研究提供了新的可能性.The study of atomic and molecular structure imaging is of great significance in revealing the microscopic nature of matter and promoting the frontier development of materials science and life science. The rapid development of femtosecond laser technology provides a new method for detecting atomic and molecular structures on an ultrafast time scale, such as strong-field tomography scheme. Strong-field tomography uses strong-field driven electron rescattering to detect the structure of oriented molecules. The advantage of this scheme is that it does not require priori knowledge of atomic differential cross-sections. Using the strong-field tomography scheme, the structural extraction of homonuclear diatomic molecules can be realized successfully. However, it is currently unclear whether this imaging scheme is applicable to the heteronuclear molecular system with more complex cross section of the electron. In this work, heteronuclear diatomic molecules are taken for example and the strong-field tomography scheme is used to study the imaging of the molecular structure. By solving the time-dependent Schrödinger equation, the variation of the photoelectron yield with the orientation angle of the molecular axis is obtained. Next, a fitting method for the variation of the photoelectron yields of the heteronuclear molecules with the orientation angle is presented, and then the fitted value of the internuclear separation is obtained. It is found that the fitting result is comparable to the real molecular internuclear separation, indicating that the strong-field tomography scheme is also suitable for the extraction of heteronuclear molecular structural information.








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