Imaging the geometrical structure of complex symmetric molecules by above-threshold ionization spectrum in an IR+XUV laser field

TL;DR

This paper proposes a novel method to image complex symmetric polyatomic molecules by analyzing high-energy interference fringes in the above-threshold ionization spectrum generated by IR+XUV laser fields, simplifying the molecular wave function.

Contribution

It introduces a frequency-domain approach using two-color laser fields to effectively image molecular structures from ATI spectra, especially in high-energy regions.

Findings

High-energy ATI spectra reveal molecular structure information.

XUV laser fields increase photoelectron kinetic energy significantly.

Interference fringes in spectra encode molecular geometry.

Abstract

Based on the frequency-domain theory, we put forward a method of imaging the complex symmetrical polyatomic molecules by using IR+XUV two-color laser fields. Although the wave function of a polyatomic molecule, such as SF6, is quite complex in momentum space, it can be simplified by several terms in the region of high value of momentum, where the destructive interference fringes from these terms carry the information of the molecular structure. In this work, we find that, since the XUV laser field may increases the kinetic energy of the photoelectron dramatically in the above-threshold ionization (ATI) process of a molecule in an IR+XUV two-color laser field, the information of the molecular structure can be obtained by analyzing the interference fringes of the ATI spectrum in the high-energy region, where the simplified wave function of the molecule plays a dominant role in this part of the ATI spectrum. This method provides a unique accessible route towards imaging polyatomic molecules from a frequency perspective.