Attosecond interferometry of shape resonances in the recoil frame of CF ₄

Abstract

Shape resonances play a central role in many areas of science, but the real-time measurement of the associated many-body dynamics remains challenging. Here, we present measurements of recoil frame angle-resolved photoionization delays in the vicinity of shape resonances of CF 4 . This technique provides insights into the spatiotemporal photoionization dynamics of molecular shape resonances. We find delays of up to ∼600 as in the ionization out of the highest occupied molecular orbital (HOMO) with a strong dependence on the emission direction and a pronounced asymmetry along the dissociation axis. Comparison with quantum-scattering calculations traces the asymmetries to the interference of a small subset of partial waves at low kinetic energies and, additionally, to the interference of two overlapping shape resonances in the HOMO-1 channel. Our experimental and theoretical results establish a broadly applicable approach to space-and time-resolved photoionization dynamics in the molecular frame.

Anisotropic dynamics of two-photon ionization: An attosecond movie of photoemission

“…However, all the aforementioned studies relied on measurements averaged over the direction of photoemission. While attosecond photoelectron interferometry has been investigated in momentum space in earlier experiments, e.g., in (26,27), including the pioneering study (28), it is only recently that orientation-resolved spectral phase measurements could be performed, using cold target recoil ion momentum spectroscopy (COLTRIMS) (29)(30)(31)(32)(33)(34) or velocity-map imaging spectroscopy (VMIS) (35)(36)(37)(38). Resonant photoemission dynamics was studied angularly with RABBIT in the vicinity of, e.g., autoionizing states (30) or shape resonances (34).…”

“…While attosecond photoelectron interferometry has been investigated in momentum space in earlier experiments, e.g., in (26,27), including the pioneering study (28), it is only recently that orientation-resolved spectral phase measurements could be performed, using cold target recoil ion momentum spectroscopy (COLTRIMS) (29)(30)(31)(32)(33)(34) or velocity-map imaging spectroscopy (VMIS) (35)(36)(37)(38). Resonant photoemission dynamics was studied angularly with RABBIT in the vicinity of, e.g., autoionizing states (30) or shape resonances (34). Using a two-color above-threshold interferometric scheme, autoionizing dynamics in chiral molecules could be angularly resolved in the laboratory frame (35).…”

A multiple scattering theoretical approach to time delay in high energy core-level photoemission of heteronuclear diatomic molecules

“…Recent developments of attosecond light sources using high-harmonic generation (HHG) combined with the advanced attosecond metrology such as attosecond streaking [1,2,3] and reconstruction of attosecond beating by interference of two-photon transitions [4,5] have enabled us to measure attosecond photoemission time delay in atoms [2,6,7], molecules [8,9,10,11,12,13,14], clusters [15], solids [1,16,17,18], and liquid [19], in the range of extreme ultraviolet wavelengths. The wavelengths of the attosecond HHG light sources have been becoming shorter and shorter and reached the water window region [20,21,22].…”

“…Here, molecular core-level photoemission time delay in a molecular frame is of particular interest. Contrary to the photoemission time delay of spherically symmetric atoms [7], molecular photoemission time delay exhibits a complex emission angle dependence in the molecular frame [10,13,14,24,25,26,27,28], which reflects the anisotropy of the molecular structure and potential. In contrast to valence-level photoemission reflecting the overall anisotropic potential [10,13,14,24], core-level photoemission may give us the atom-resolved potential and geometrical information [25] and temporal signature of the entangled nuclear and electronic motion in the photoemission process [29].…”

“…Contrary to the photoemission time delay of spherically symmetric atoms [7], molecular photoemission time delay exhibits a complex emission angle dependence in the molecular frame [10,13,14,24,25,26,27,28], which reflects the anisotropy of the molecular structure and potential. In contrast to valence-level photoemission reflecting the overall anisotropic potential [10,13,14,24], core-level photoemission may give us the atom-resolved potential and geometrical information [25] and temporal signature of the entangled nuclear and electronic motion in the photoemission process [29]. Multiple scattering theory [30] may be a workhorse to analyze the anisotropic molecular structure and potential as well as nuclear and electronic dynamics hidden in the core-level photoemission time delay in the molecular frame.…”