As a fast-developing technique for in situ multi-element analysis method, laser induced breakdown spectroscopy - LIBS is, however, developing slowly on liquid analysis due to some technical difficulties. We propose a new method, namely capillary mode, to quantify the concentrations of the elements in solution using LIBS. A Nd:YAG laser with repetition of 10 Hz were used to analyze the solution of Na₂CrO₄ and no any sample preparation in measurements. The experimental results show that the splashing of liquid induced by laser pulses is decreased significantly and the pollution of mirrors is avoided effectively using liquid capillary mode. The results of quantitative analysis for liquid are also improved than other method. The calibration curves of Cr and Na are well characterized by straight lines and the regression coefficient values of the linear fit are better than 0.998. The limits of detection (LODs) of Cr and Na are determined to be 28.9 mg/L and 1.0 mg/L in this work, respectively. The experimental results show that the liquid capillary mode provides a more practical and very simple approach to improve accuracy of quantitative element analysis in liquids by LIBS technique.

Electron emission from the single-electron capture with simultaneous single ionization in 30 keV/u He2+ on argon was investigated using a reaction microscope, providing the electron energy spectra and momentum distributions. Intensive peaks for electrons with near-zero kinetic energies have been observed. It is demonstrated that mechanisms contributing to the electron emission include direct transfer ionization (DTI), double-electron capture with autoionization (DECA), and single-electron capture with autoionization (SECA) of target. Comparison of resonance energies shows that Ar+ ions in SECA decay mainly through the 3s3p53d states by emitting Auger electrons, and He** in DECA decay through the 2l2l$'${} states. The dependence of electron emission on the transverse momentum exchange has been studied. In the transfer ionization channel studied here, the DTI process dominates the electron emission, and no saddle point electron mechanism has been found.

We measured the kinetic energy distributions of the fragment ions of doubly and quadruply ionized argon dimers using 3000 eV electron impact. For the dissociation of (Ar${}_2$)${}^{2+}$, the peak that indicates radiative charge transfer is observed, where the outer-shell ionization (dominant in highly charged ion collision) and the inner-shell ionization (preferential in x-ray experiments) have approximately equal contributions. For the dissociation of (Ar${}_2$)${}^{4+}$, the interatomic Coulombic decay and electron-transfer-mediated decay are first observed in the electron-impact process.

Charge exchange between highly charged ions and neutral atoms and molecules has been considered as one of the important mechanisms controlling soft X-ray emissions in many astrophysical objects and environments. However, for modeling charge exchange soft X-ray emission, the data of n- and l-resolved state-selective capture cross sections are often obtained by empirical and semiclassical theory calculations. With a newly built cold target recoil-ion momentum spectroscopy (COLTRIMS) apparatus, we perform a series of measurements of the charge exchange of Ne^(8,9)+ ions with He and H₂ for collision energy ranging from 1 to 24.75 keV/u. n-resolved state-selective capture cross sections are reported. By comparing the measured state-selective capture cross sections to those calculated by the multichannel Landau–Zener method (MCLZ), it is found that MCLZ calculations are in good agreement with the measurement for the dominant n capture for He target. Furthermore, by using nl-resolved cross sections calculated by MCLZ and applying l distributions commonly used in the astrophysical literature to experimentally derived n-resolved cross sections, we calculate the soft X-ray emissions in the charge exchange between 4 keV/u Ne⁸⁺ and He by considering the radiative cascade from the excited Ne⁷⁺ ions. Reasonable agreement is found in comparison to the measurement for even and separable models, and MCLZ calculations give results in a better agreement.

An experimental investigation of the breakup of ${\left(\mathrm{C}{\mathrm{O}}_2\right)}^{3+}$ induced by $\mathrm{N}{\mathrm{e}}^{4+}$ ion impact at incident energies of 1.12 MeV was performed. By analyzing the momentum distributions and the kinetic energies of the three fragment ions, the nonsequential and sequential dissociation mechanisms are verified. In contrast to highly charged ion impact, two different sequential decay pathways were observed in the present experiment. One pathway originates from the primary cation ${\left(\mathrm{C}{\mathrm{O}}_2\right)}^{3+}$ populated into ${}^4\mathrm{\Sigma }^{+}$ states by collision charge exchange and its daughter cation ${\left(\mathrm{CO}\right)}^{2+}$ populated into the two excited states (${}^3\mathrm{\Pi }$ and $X{}^1\mathrm{\Pi }$) by the first fragmentation step, resulting in a lower KER peak. The other pathway originates from the primary cation ${\left(\mathrm{C}{\mathrm{O}}_2\right)}^{3+}$ locating at ${}^6\mathrm{\Pi }$ state, and its daughter cation ${\left(\mathrm{CO}\right)}^{2+}$ populated into the metastable excited states ${}^3\mathrm{\Pi }$, $X{}^1\mathrm{\Pi }$, and ${}^3\mathrm{\Sigma }^{+}$, leading to the higher KER peak. Our work is a breakup experiment of ${\left(\mathrm{C}{\mathrm{O}}_2\right)}^{3+}$ presenting the initial states of the parent cation ${\left(\mathrm{C}{\mathrm{O}}_2\right)}^{3+}$ and the metastable states of $\mathrm{C}{\mathrm{O}}^{2+}$ ion simultaneously.

We publish three Roadmaps on photonic, electronic and atomic collision physics in order to celebrate the 60th anniversary of the ICPEAC conference. Roadmap III focusses on heavy particles: with zero to relativistic speeds. Modern theoretical and experimental approaches provide detailed insight into the wide range of many-body interactions involving projectiles and targets of varying complexity ranging from simple atoms, through molecules and clusters, complex biomolecules and nanoparticles to surfaces and crystals. These developments have been driven by technological progress and future developments will expand the horizon of the systems that can be studied. This Roadmap aims at looking back along the road, explaining the evolution of the field, and looking forward, collecting nineteen contributions from leading scientists in the field.