High-Resolution Imaging of C + He Collisions using Zeeman Deceleration and Vacuum-Ultraviolet Detection

Abstract

High-resolution measurements of angular scattering distributions provide a sensitive test for theoretical descriptions of collision processes. Crossed beam experiments employing a decelerator and velocity map imaging have proven successful to probe collision cross sections with extraordinary resolution. However, a prerequisite to exploit these possibilities is the availability of a near-threshold state-selective ionization scheme to detect the collision products, which for many species is either absent or inefficient. We present the first implementation of recoil-free vacuum ultraviolet (VUV) based detection in scattering experiments involving a decelerator and velocity map imaging. This allowed for high-resolution measurements of state-resolved angular scattering distributions for inelastic collisions between Zeeman-decelerated carbon C( 3 P 1 ) atoms and helium atoms. We fully resolved diffraction oscillations in the angular distributions, which showed excellent agreement with the distributions predicted by quantum scattering calculations. Our approach offers exciting prospects to investigate a large range of scattering processes with unprecedented precision.

Low-temperature reaction dynamics of paramagnetic species in the gas phase

“… 145 More recently, angular scattering distributions for inelastic collisions between Zeeman-decelerated C( 3 P 1 ) and He atoms have been reported using a crossed-beam set-up. 146 Oscillatory patterns were once again observed due to the diffraction of matter waves, with the angular scattering distributions in close agreement with simulations obtained from quantum-mechanical close-coupling calculations.…”

Low-Energy Collisions of Zeeman-Decelerated NH Radicals with He Atoms

“…The experiments are performed in the molecular beam apparatus schematically depicted in Figure , which was recently used to decelerate beams of O atoms, O 2 molecules, NO (X 2 Π 3/2 ) radicals, NH radicals, and C atoms . The experiment was operated at a repetition rate of 20 Hz.…”

“…The experiments are performed in the molecular beam apparatus schematically depicted in Figure 1 , which was recently used to decelerate beams of O atoms, O 2 molecules, 38 NO (X 2 Π 3/2 ) radicals, 14 NH radicals, 16 and C atoms. 15 The experiment was operated at a repetition rate of 20 Hz. A detailed description of the mechanical and electronic implementation of the decelerator, as well as details on the production and deceleration of NH radicals, are given elsewhere.…”

“…Zeeman decelerators, the magnetic analogue of Stark decelerators, have been developed as well and have successfully been used to slow a variety of species and to load them into traps; see reviews in refs − and references contained within. Recently, the first successful crossed beam scattering experiments using a Zeeman decelerator have been performed, focusing on inelastic processes involving NO radicals or C atoms. , Despite these important proof-of-principle advances, crossed beam scattering using Zeeman decelerators is still in its infancy, and the full potential of the technique to probe scattering processes has yet to be unlocked. In particular, it is important to investigate whether the technique can be used for sensitive measurements on a large variety of species and whether low collision energies are achievable.…”

Viewpoints on the 11th International Meeting on Atomic and Molecular Physics and Chemistry

“…Particularly, he described the electronic structure and multichannel quantum scattering calculations for 138 Ba + ion colliding with 6 Li, guiding and confirming the recent experiments in Freiburg of magnetically tunable Feshbach resonances observed in the process. 32 The Wednesday program was closed by the invited talk of Jolijn Onvlee reporting on the development of a molecular beam setup combining Zeeman deceleration and Velocity Map Imaging to study quantum state-resolved collision dynamics of neutrals, such as carbon with helium atoms 33 and carbon atoms with hydrogen molecules.…”