A Hard Sphere Model for Bimolecular Recombination of Heavy Ions

We propose a hard sphere model of bimolecular recombination RM+ + X– → MX + R, where M+ is an alkali ion, X– is a halide ion, and R is a neutral rare gas or mercury atom. Calculations are carried out for M+ = Cs+, X– = Br–, R = Ar, Kr, Xe, Hg, for collision energies in the range from 1 to 10 eV, and for distributions of the RM+ complex internal energy corresponding to temperatures of 500, 1000, and 2000 K. The excitation functions and opacity functions of bimolecular recombination in the hard sphere approximation are found, and the classification of the collisions according to the sequences of pairwise encounters of the particles is considered. In more than half of all the cases, recombination occurs due to a single impact of the Br– ion with the R atom. For the recombination XeCs+ + Br–, the hard sphere model enables one to reproduce the most important characteristics of the collision energy dependence of the recombination probability obtained within the framework of quasiclassical trajectory calculations.

Study of Ne:He Plasma of a Periodically Pulsed Discharge for Optically Pumped Rare Gas Laser

Optically pumped rare gas lasers (OPRGL) suggested recently as a chemically inert analog of diode-pumped alkali lasers are under extensive study at present. OPRGLs employ metastable atoms of heavier rare gases (Rg*) in He bath produced in discharge plasma. Ar* OPRGL is the most popular system at present, due to presence of a narrow band diode pump and abundance of Ar. However, Ne* OPRGL is interesting due to its visible lasing wavelength at 703.2 nm nm and presence of channels of energy transfer in Ne-He plasma that facilitate Ne* production. We present the first results of experiments with Ne* OPRGL that include Ne* number density in its active medium, and lasing experiments to determine pumping threshold for s5 → p9 transition in a transverse pumping configuration using a narrow band pulsed dye laser as a pump.

Trends and Advances in Inductively Coupled Plasma Tandem Quadruple Mass Spectrometry (ICP-QMS/QMS) With Reaction Cell

Trends and advances in the development and application of inductively coupled plasma tandem quadrupole mass spectrometry (ICP-QMS/QMS) with a reaction cell is reviewed mainly based on publications from January 2018 to July 2021. ICP-QMS/QMS has been applied in various research fields covering the sciences of biology, energy, environmental, food/medical, geology, materials, and radionuclide. The objectives of analysis cover the determination of elemental concentration, ion-gas reaction, isotope analysis, single particle analysis, and chemical speciation analysis. Measurement of most elements in the periodic table are reported except for H, N, O, F, rare gas, and some of the radionuclides. In addition to the default reaction/collision gases (i.e., He, H2, O2, and NH3), N2O, CO2, CH4, CH3F, C2H4, and C2H6 have been used as reaction gases to improve the capability of separating spectral interferences or to study the ion-molecule reactions. Typical applications of ICP-QMS/QMS analysis in the major research fields are also discussed.