Quantum-beat photoelectron-imaging spectroscopy of Xe in the VUV

Abstract

Time-resolved pump-probe measurements of Xe, pumped at 133 nm and probed at 266 nm, are presented.The pump pulse prepared a long-lived hyperfine wavepacket, in the Xe.57 eV). The wavepacket was monitored via single-photon ionization, and photoelectron images measured. The images provide angle-and timeresolved data which, when obtained over a large time-window (900 ps), constitute a precision quantum beat spectroscopy measurement of the hyperfine state splittings. Additionally, analysis of the full photoelectron image stack provides a quantum beat imaging modality, in which the Fourier components of the photoelectron images correlated with specific beat components can be obtained. This may also permit the extraction of isotope-resolved photoelectron images in the frequency domain, in cases where nuclear spins (hence beat components) can be uniquely assigned to specific isotopes (as herein), and also provides phase information. The information content of both raw, and inverted, image stacks is investigated, suggesting the utility of the Fourier analysis methodology in cases where images cannot be inverted.

The Sulfolene Protecting Group: Observation of a Direct Photoinitiated Cheletropic Ring Opening

“…TRPES data was collected using the experimental setup described previously [52,53] . 2,5‐Dihydrothiophene‐ 1,1‐dioxide (Sigma‐Aldrich, 98 %, used without further purification) was prepared by annealing onto filter‐paper at 100 °C followed by cooling to room‐temperature.…”

“…The compound was expanded at a backing pressure of 1.1 bar via an Even‐Lavie pulsed valve held at 70 °C, through a 250 μm nozzle into a sample chamber (pressure ∼10 −5 mbar) in a supersonic molecular beam. The beam was skimmed before entering the interaction chamber (pressure ∼10 −9 mbar), containing a detector scheme described previously [52,53] . The optical setup is described in detail by Forbes [52] .…”

Modulation of quantum beats signal upon photoionization of Xe isotopes in the magnetic field

“…In the publication in 2018 by Forbes et al [16], it is proposed to investigate the effects of atomic states interference within the quantum beat spectroscopy (QBS) technique, where the beats themselves are observed in a photoelectronic image. The rationale for applicability of the QBS technique to studying the fine splitting in atoms of noble gases and atoms of alkali metals is based on the coincidence of nanosecond and picosecond time scales of the experiment with lifetimes and inverse frequency intervals typical for the fine structure.…”

Spatiotemporal imaging of valence electron motion

“…Such images can be obtained indirectly by analyzing the high harmonic spectrum as a function of molecular alignment with respect to the laser polarization [7,20,21], or directly, by measuring the photoelectron angular distribution in the molecular frame [9,[22][23][24]. Photoelectron angular distributions have been studied to follow electron dynamics on a sub-picosecond time scale [25,26]. However, the direct imaging of bound electron wave packets on the femtosecond time-scale has yet to be accomplished.…”