Two-center Interference in the Photoionization Delays of Kr2

TL;DR

This paper reports the experimental observation of two-center interference effects in the photoionization delays of Kr2, revealing oscillations in delay times due to wave packet interference, supported by quantum calculations.

Contribution

It demonstrates the first measurement of two-center interference in photoionization delays of a diatomic molecule using attosecond spectroscopy, combining experimental and theoretical approaches.

Findings

Oscillations in photoionization delay as a function of electron energy.

Interference effects arise from wave packets emitted or scattered from two atomic centers.

Theoretical models support the experimental observations.

Abstract

We present the experimental observation of two-center interference in the ionization time delays of Kr2. Using attosecond electron-ion-coincidence spectroscopy, we simultaneously measure the photoionization delays of krypton monomer and dimer. The relative time delay is found to oscillate as a function of the electron kinetic energy, an effect that is traced back to constructive and destructive interference of the photoelectron wave packets that are emitted or scattered from the two atomic centers. Our interpretation of the experimental results is supported by solving the time-independent Schrodinger equation of a 1D double-well potential, as well as coupled-channel multiconfigurational quantum-scattering calculations of Kr2. This work opens the door to the study of a broad class of quantum-interference effects in photoionization delays and demonstrates the potential of attosecond coincidence spectroscopy for studying weakly bound systems.