Multiply charged cluster ion crossed-beam apparatus: Multi-ionization of clusters by ion impact

Abstract

An experimental setup is described, which is used to multi-ionize neutral clusters and to study their stability and the importance of different decay processes. Clusters are ionized in collisions with slow multiply charged ions (projectile charge z ranging from 1 to 30, kinetic energies ranging from 1 to 20 keV/charge). Both ion and cluster beamlines, as well as the characteristics of the analysis and detection systems, are described. Collisions with highly charged ions such as Ar8+ or Xe30+ turn out to be efficient tools in preparing clusters in high charge states without increasing significantly their internal temperature. Measurements performed in coincidence with the number of electrons stabilized by the projectile ion after the collision allowed us to control the charge and the excitation energy of the ionized system. The efficiency of the method is demonstrated for sodium clusters and C60 molecules.

Formation and Fragmentation of Protonated Molecules after Ionization of Amino Acid and Lactic Acid Clusters by Collision with Ions in the Gas Phase

“…[32] In brief, molecular clusters were formed in ag as aggregation chamber filled with ac ooled buffer gas (He) at ap ressure of af ew millibars. Molecules were evaporated in ar esistively heated oven and carried by the He toward ac ondensation channel cooled with liquid nitrogen where they aggregate.…”

“…As single ionization by singly charged projectiles occurs at as maller mean impact parameter compared to multiply charged projectile ions, one can expect ah ighert ransfer of excitation energyd uring the collisions involving the former. [32,33] The ratios of radical cations to protonated lactic acid monomers together with the corresponding uncertainties are reported in Table 1. These ratios were determined from the area of the two fitting Gaussian functions (Figure 2), andu ncertainties on both their amplitude and width were taken into account.…”

Determination of Energy-Transfer Distributions in Ionizing Ion-Molecule Collisions

“…1(a)] was produced by heating a powder in an oven at a temperature low enough to avoid thermal decomposition [20]. Both experimental setups have been described in detail elsewhere [21,22] and a brief description is given in the Supplemental Material [23].…”

Formations of DumbbellC118andC119inside Clusters ofC60Zettergren1, Rousseau2, Wang3 et al. 2013Phys. Rev. Lett.Self Cite662480View full textAdd to dashboardCite

“…There, a 22.5 keV He 2þ ion beam was produced in an ECR ion source and chopped into 0:5 s long pulses at a rate of 1.9 kHz. These projectile ions interact with clusters of fullerenes from a liquid nitrogen cooled cluster aggregation source operated with a flow of He gas [14]. The cold source produces neutral van der Waals clusters following a broad lognormal size distribution [15].…”