Search arXiv⌕ Search
Home/Archive/arXiv

arXiv · 1502.04007

Velocity map imaging with non-uniform detection: quantitative molecular axis alignment measurements via Coulomb explosion imaging

Jonathan G. Underwood·I. Procino·L. Christiansen·J. Maurer·H. Stapelfeldt
View original source ↗Read source document ↗Export metadata ↓

Abstract

We present a method for inverting charged particle velocity map images which incoorporates a non-uniform detection function. This method is applied to the specific case of extracting molecular axis alignment from Coulomb explosion imaging probes in which the probe itself has a dependence on molecular orientation which often removes cylindrical symmetry from the experiment and prevents the use of standard inversion techniques for the recovery of the molecular axis distribution. By incorporating the known detection function, it is possible to remove the angular bias of the Coulomb explosion probe process and invert the image to allow quantitative measurement of the degree of molecular axis alignment.

Explore related subjects

physics.chem-phphysics.ins-det

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

Jonathan G. Underwood, I. Procino, L. Christiansen, J. Maurer, H. Stapelfeldt. 2015-07-08. Velocity map imaging with non-uniform detection: quantitative molecular axis alignment measurements via Coulomb explosion imaging. https://doi.org/10.1063/1.4922137

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related papers

arXiv2026

Resolving the Marcus-Rehm-Weller Paradox in Electron Transfer

Marcus theory famously predicts that electron-transfer rates decrease once the thermodynamic driving force exceeds the reorganization energy. Yet many systems instead exhibit Rehm-Weller kinetics characterized by rate saturation rather than decrease. Here we show that these apparently contradictory phenomenologies emerge as opposite physical limits of the same two-state quantum Hamiltonian. In the normal region, the model recovers both Marcus and Rehm-Weller behavior. In the inverted region, however, it predicts Marcus's decreasing rate in the nonadiabatic limit but Rehm-Weller saturation in the adiabatic limit. Using physically realistic reorganization energies and electronic coupling values, we show that Rehm-Weller's data can be quantitatively reproduced within a microscopic quantum model without invoking phenomenological corrections.

physics.chem-ph↗
arXiv2026

Resolving electronic evolution during bond dissociation

Coupled electronic and nuclear motions govern chemical reactions, yet resolving how electronic structure evolves during bond dissociation remains a central challenge. Here we investigate the photodissociation of Br2 using correlated photoelectron photoion coincidence measurements. A 400 nm pulse initiates dissociation, while strong field ionization probes the evolving molecular system. Coincident measurement of three dimensional photoion and photoelectron momenta provides simultaneous access to the internuclear separation and the accompanying electronic evolution. We identify multiple distinct stages of electronic evolution during bond dissociation. The reshaping of the ionizing molecular orbital occurs first, followed by redistribution and localization of the electronic charge density, and finally by the gradual decay of residual electronic coherence between the separating atomic centers. Between the molecular and atomic limits, we observe an intermediate bond-breaking state in which localized atomic character coexists with a partially delocalized electronic response. By combining correlated observables with semiclassical modelling, we resolve the temporal ordering of these coupled electronic and nuclear processes and determine their associated dynamical timescales. These results demonstrate how correlated momentum observables can disentangle different aspects of the molecular-to-atomic transition.

physics.chem-ph↗
arXiv2026

A reduced-cost two-component relativistic equation-of-motion coupled cluster method for the double electron attachment problem

We present a computationally efficient relativistic formulation of the equation-of-motion coupled-cluster (EOM-CC) method for the double electron attachment (DEA) problem. In this work, the exact two-component Hamiltonian within the atomic mean-field approximation is employed, yielding results that are in close agreement with the corresponding four-component calculations. However, canonical DEA-EOM-CCSD calculations become prohibitively expensive for heavy elements and large basis sets due to the substantial memory requirements associated with the complex-valued 3p1h excitation manifold. To address this limitation, we introduce a new state-specific frozen natural spinor basis that significantly reduces the virtual space through two controllable truncation thresholds. Furthermore, the use of Cholesky decomposition for the two-electron integrals provides an additional reduction in memory requirements. The performance of the proposed approach is demonstrated through calculations of double ionization potentials and excitation energies for group-12 and group-14 heavy elements. Vertical excitation energies for heavy chalcogen dimers are also presented. In addition, a range of diatomic spectroscopic constants is evaluated for group-13 hydrides. Finally, the method is applied to predict the singlet-triplet gaps of dihalocarbenes, indicating that an accurate description of these systems may require excitation manifolds beyond the 3p1h space.

physics.chem-ph↗