Transverse asymmetry in molecular strong-field photoelectron holography induced by initial phase structure and Coulomb field

Transverse asymmetry (TA) signifies a feature of the photoelectron momentum distribution (PMD) when linearly polarized light interacts with tilted molecules, which has been widely employed in strong-field photoelectron holography. The initial phase structure and the asymmetric Coulomb field are considered as two different physical origins for the TA. Through the molecular quantum trajectory Monte Carlo method, we correct some misconceptions in previous studies and refine the physical picture regarding how these two factors modulate TA in PMDs. We demonstrate the critical influence of the multiple-constituent atomic orbitals for ionizing the molecular orbital on the initial phase structure. This phase structure introduces an additional phase difference between tunneling electrons, leading to the rotation of the spiderlike and comblike fringes while maintaining the structure of the above-threshold ionization rings. In contrast, the asymmetric Coulomb field modulates the amplitude distribution of tunneling electrons depending on the tunneling sites, resulting in changes in the intensity of the fringes. Additionally, apart from the TA signal induced by the asymmetric Coulomb field for the indirect electrons, we also identified the reverse TA signal for the direct ones near zero momentum.