Methods for experimental reconstruction of molecular frame (MF) photoionization dynamics, and related properties - specifically MF photoelectron angular distributions (PADs) and continuum density matrices - are outlined and discussed. General concepts are introduced for the non-expert reader, and experimental and theoretical techniques are further outlined in some depth. Particular focus is placed on a detailed example of numerical reconstruction techniques for matrix-element retrieval from time-domain experimental measurements making use of rotational-wavepackets (i.e. aligned frame measurements) - the ``bootstrapping to the MF" methodology - and a matrix-inversion technique for direct MF-PAD recovery. Ongoing resources for interested researchers are also introduced, including sample data, reconstruction codes (the Photoelectron Metrology Toolkit, written in python, and associated Quantum Metrology with Photoelectrons platform/ecosystem), and literature via online repositories; it is hoped these resources will be of ongoing use to the community.

ABSTRACT Angle-resolved (AR) RABBIT measurements offer a high information content measurement scheme, due to the presence of multiple, interfering, ionization channels combined with a phase-sensitive observable in the form of angle and time-resolved photoelectron interferograms. In order to explore the characteristics and potentials of AR-RABBIT, a perturbative 2-photon model is developed; based on this model, example AR-RABBIT results are computed for model and real systems, for a range of RABBIT schemes. These results indicate some of the phenomena to be expected in AR-RABBIT measurements, and suggest various applications of the technique in photoionization metrology.

_Article details_ Software metapaper, structured for the Journal of Open Research Software (JORS). Online version (Authorea) can be found at https://www.authorea.com/users/71114/articles/122402/_show_article Github (software repository): github.com/phockett/ePSproc Figshare repository (manuscript & source files): DOI: 10.6084/m9.figshare.3545639 10/08/16 - This fork for review. 12/11/16 - arXiv version uploaded, 1611.04043 03/09/19 - Finally working on a python version, see Github pages for updates. Full documentation now on on Read the Docs.

_Additional notes:_ Authors: - Paul Hockett, National Research Council of Canada, 100 Sussex Drive, Ottawa, K1A 0R6, Canada - Tim Ingleby, Department of Architecture and Built Environment, Northumbria University, Ellison Place, Newcastle upon Tyne, NE1 8ST, UK Links: - Online version: Authorea, DOI: 10.22541/au.148821660.05483993 - Repository for videos and files, Figshare, DOI: 10.6084/m9.figshare.c.3470907 - Arxiv version (1610.04281) - Ongoing work: femtolab.ca

_Publication history_ - Original document (Authorea), DOI: 10.22541/au.149030711.19068540. - arXiv 1702.00744 (Feb. 2017) - J. Chem. Phys. special issue “Developments and Applications of Velocity Mapped Imaging Techniques”, (March 2017), DOI: 10.1063/1.4978923 - Data and analysis scripts (OSF), DOI: 10.17605/OSF.IO/RRFK3. _See also_ - AIP Press Release: _The Inner Lives of Molecules_ (April 2017) - PImMS camera website - Vallance group website - Femtolab website

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 5p⁵(²P1/2∘)6s ²[1/2]₁∘ manifold (E=77185 cm −1=9.57 eV). The wavepacket was monitored via single-photon ionization, and photoelectron images measured. The images provide angle- and time-resolved 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.