Vacuum upgrade and enhanced performances of the double imaging electron/ion coincidence end-station at the vacuum ultraviolet beamline DESIRS

Abstract

We report here the recent upgrade of the SAPHIRS permanent photoionization end-station at the DESIRS vacuum ultraviolet beamline of synchrotron SOLEIL, whose performances have been enhanced by installing an additional double-skimmer differential chamber. The smaller molecular beam profile obtained at the interaction region has increased the mass resolution of the double imaging photoelectron photoion coincidence (i(2)PEPICO) spectrometer, DELICIOUS III, installed in the photoionization chamber of the SAPHIRS endstation, by a factor of two, to M/ΔM ∼ 1700 (FWHM). The electron kinetic energy resolution offered by the velocity map imaging (VMI) part of the spectrometer has been improved down to 2.8% (ΔE/E) as we show on the N2 photoionization case in the double skimmer configuration. As a representative example of the overall state-of-the-art i(2)PEPICO performances, experimental results of the dissociation of state-selected O2(+)(B(2)∑(g)(-), v(+) = 0-6) molecular ions performed at the fixed photon energy of hν = 21.1 eV are presented.

Determination of accurate electron chiral asymmetries in fenchone and camphor in the VUV range: sensitivity to isomerism and enantiomeric purity

“…A complete description of the DELICIOUS3 i 2 PEPICO spectrometer used in this work and its performances has been reported elsewhere 45,49 . Briefly, it consists of an electron velocity map imaging (VMI) analyser coupled to a modified ion Wiley--McLaren imaging spectrometer.…”

“…PECD experiments were performed on the SAPHIRS endstation 45 of the VUV synchrotron beamline DESIRS 46 , at the French synchrotron facility SOLEIL. Each enantiomer of each molecule was directly placed into a temperature--controlled in--vacuum stainless steel oven.…”

Effect of electronic angular momentum exchange on photoelectron anisotropy following the two-color ionization of krypton atoms

“…The experiments were performed at the vacuum ultra-violet (VUV) variable polarization beamline DESIRS, 21 of synchrotron SOLEIL, together with the molecular beam chamber SAPHIRS 22 and the DELICIOUS III double imaging particle coincidence spectrometer. 23 A supersonic beam of pure Kr, produced by expanding 1 bar of Kr through a 70 µm nozzle, was doubly skimmed and crossed with counter-propagating SR and laser beams, each of which could be linearly (LP), leftcircularly (LCP) or right-circularly (RCP) polarized.…”

“…The typical photoelectron kinetic energy resolution that can be achieved at the edge of the detector is about 3%. 22 The images were inverted using the pBasex software, 26 which provides both the photoelectron intensity and the angular distribution parameters as a function of the photoelectron kinetic energy. The pBasex method is applicable when the images have cylindrical symmetry.…”

Photoelectron angular distributions from rotationally resolved autoionizing states of N2

“…The two studies gave qualitatively similar results for the vibrational branching ratios and photoelectron angular distributions, but some significant quantitative differences were noted at low electron energies. 7 In this paper, we present new results on the near-threshold photoionization of molecular nitrogen by making use of the high-resolution vacuum-ultraviolet (VUV) light provided at the DESIRS end station of the Synchrotron SOLEIL 31 and the DELICIOUS III imaging photoelectron-photoion coincidence spectrometer 32,33 that allows the recording of electron energy and angular distributions across the region of interest. While the electron spectrometer resolution is not sufficient to resolve the final N 2 + X 2 Σ g + , v + = 0 rotational distributions, the photon resolution is sufficient to resolve rotational structure in the excitation process for most of the observed bands.…”