A clear understanding of the mechanisms that control the electron dynamics in a strong laser field is still a challenge that requires interpretation by advanced theory. Development of accurate theoretical and computational methods, able to provide a precise treatment of the fundamental processes generated in the strong field regime, is therefore crucial. A central aspect is the choice of the basis for the wave function expansion. Accuracy in describing multiphoton processes is strictly related to the intrinsic properties of the basis, such as numerical convergence, computational cost, and representation of the continuum. By explicitly solving the 1D and 3D time-dependent Schrödinger equation for H2+ in the presence of an intense electric field, we explore the numerical performance of using a real-space grid, a B-spline basis, and a Gaussian basis (improved by optimal Gaussian functions for the continuum). We analyze the performance of the three bases for high-harmonic generation and above-threshold ionization for H2+. In particular, for high-harmonic generation, the capability of the basis to reproduce the two-center interference and the hyper-Raman phenomena is investigated.

中文翻译：

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强激光场中电子动力学的最佳基础集：分子离子H2的情况。

清楚地了解在强激光场中控制电子动力学的机制仍然是一个挑战，需要高级理论加以解释。因此，开发精确的理论和计算方法以能够对强磁场条件下产生的基本过程进行精确处理至关重要。一个中心方面是波动函数扩展基础的选择。描述多光子过程的准确性与基础的固有属性严格相关，例如数值收敛，计算成本和连续体表示。在存在强电场的情况下，通过明确求解H2 +的1D和3D时间相关的Schrödinger方程，我们探索了使用实空间网格，B样条曲线的数值性能，和高斯基础（通过针对连续体的最佳高斯函数进行改进）。我们分析了高谐波产生和H2 +阈值以上电离的三个碱基的性能。特别是对于高次谐波的产生，研究了重现两中心干扰和超拉曼现象的基础的能力。