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1. Intensity dependence of multiply charged atomic ions from argon clusters in moderate nanosecond laser fields

   https://doi.org/10.1063/5.0065086  

   Yao, Yuzhong ; Zhang, Jie ; Pandey, Rahul ; Wu, Di ; Kong, Wei ; Xue, Lan ( October 2021 , The Journal of Chemical Physics)
2. Resolving Isomers of Star-Branched Poly(Ethylene Glycols) by IMS-MS Using Multiply Charged Ions

   https://doi.org/10.1021/jasms.0c00045  

   Austin, Calvin A. ; Inutan, Ellen D. ; Bohrer, Brian C. ; Li, Jing ; Fischer, Joshua L. ; Wijerathne, Kanchana ; Foley, Casey D. ; Lietz, Christopher B. ; Woodall, Daniel W. ; Imperial, Lorelie F. ; et al ( January 2020 , Journal of the American Society for Mass Spectrometry)

   null (Ed.)

   Ion mobility spectrometry (IMS) mass spectrometry (MS) centers on the ability to separate gaseous structures by size, charge, shape, and followed by mass-to-charge (m/z). For oligomeric structures, improved separation is hypothesized to be related to the ability to extend structures through repulsive forces between cations electrostatically bonded to the oligomers. Here we show the ability to separate differently branched multiply charged ions of star-branched poly(ethylene glycol) oligomers (up to 2000 Da) regardless of whether formed by electrospray ionization (ESI) charged solution droplets or from charged solid particles produced directly from a surface by matrix-assisted ionization. Detailed structural characterization of isomers of the star-branched compositions was first established using a home-built high-resolution ESI IMS-MS instrument. The doubly charged ions have well-resolved drift times, achieving separation of isomers and also allowing differentiation of star-branched versus linear oligomers. An IMS-MS “snapshot” approach allows visualization of architectural dispersity and (im)purity of samples in a straightforward manner. Analyses capabilities are shown for different cations and ionization methods using commercially available traveling wave IMS-MS instruments. Analyses directly from surfaces using the new ionization processes are, because of the multiply charging, not only associated with the benefits of improved gas-phase separations, relative to that of ions produced by matrix-assisted laser desorption/ionization, but also provide the potential for spatially resolved measurements relative to ESI and other ionization methods. 

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3. Measurement of the collision rate coefficients between atmospheric ions and multiply charged aerosol particles in the CERN CLOUD chamber

   https://doi.org/10.5194/acp-23-6703-2023  

   Pfeifer, Joschka ; Mahfouz, Naser G. ; Schulze, Benjamin C. ; Mathot, Serge ; Stolzenburg, Dominik ; Baalbaki, Rima ; Brasseur, Zoé ; Caudillo, Lucia ; Dada, Lubna ; Granzin, Manuel ; et al ( January 2023 , Atmospheric Chemistry and Physics)

   Abstract. Aerosol particles have an important role in Earth'sradiation balance and climate, both directly and indirectly throughaerosol–cloud interactions. Most aerosol particles in the atmosphere areweakly charged, affecting both their collision rates with ions and neutralmolecules, as well as the rates by which they are scavenged by other aerosolparticles and cloud droplets. The rate coefficients between ions and aerosolparticles are important since they determine the growth rates and lifetimesof ions and charged aerosol particles, and so they may influence cloudmicrophysics, dynamics, and aerosol processing. However, despite theirimportance, very few experimental measurements exist of charged aerosolcollision rates under atmospheric conditions, where galactic cosmic rays inthe lower troposphere give rise to ion pair concentrations of around 1000 cm−3. Here we present measurements in the CERN CLOUD chamber of therate coefficients between ions and small (<10 nm) aerosol particlescontaining up to 9 elementary charges, e. We find the rate coefficient of asingly charged ion with an oppositely charged particle increases from 2.0(0.4–4.4) × 10−6 cm3 s−1 to 30.6 (24.9–45.1) × 10−6 cm3 s−1 for particles with charges of 1 to9 e, respectively, where the parentheses indicate the ±1σuncertainty interval. Our measurements are compatible with theoreticalpredictions and show excellent agreement with the model ofGatti and Kortshagen (2008). 

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4. Two- and three-body fragmentation of multiply charged tribromomethane by ultrafast laser pulses

   https://doi.org/10.1039/d2cp03089f  

   Bhattacharyya, Surjendu ; Borne, Kurtis ; Ziaee, Farzaneh ; Pathak, Shashank ; Wang, Enliang ; Venkatachalam, Anbu Selvam ; Marshall, Nathan ; Carnes, Kevin D. ; Fehrenbach, Charles W. ; Severt, Travis ; et al ( November 2022 , Physical Chemistry Chemical Physics)

   We investigate the two- and three-body fragmentation of tribromomethane (bromoform, CHBr 3 ) resulting from multiple ionization by 28-femtosecond near-infrared laser pulses with a peak intensity of 6 × 10 14 W cm −2 . The analysis focuses on channels consisting exclusively of ionic fragments, which are measured by coincidence momentum imaging. The dominant two-body fragmentation channel is found to be Br + + CHBr 2 + . Weaker HBr + + CBr 2 + , CHBr + + Br 2 + , CHBr 2+ + Br 2 + , and Br + + CHBr 2 2+ channels, some of which require bond rearrangement prior to or during the fragmentation, are also observed. The dominant three-body fragmentation channel is found to be Br + + Br + + CHBr + . This channel includes both concerted and sequential fragmentation pathways, which we identify using the native frames analysis method. We compare the measured kinetic energy release and momentum correlations with the results of classical Coulomb explosion simulations and discuss the possible isomerization of CHBr 3 to BrCHBr–Br (iso-CHBr 3 ) prior to the fragmentation. 

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5. Dynamics of low- and high-Z metal ions emitted during nanosecond laser-produced plasmas

   https://doi.org/10.1063/1.4967161  

   Elsied, Ahmed M. ; Diwakar, Prasoon K. ; Polek, Mathew ; Hassanein, Ahmed ( November 2016 , Journal of Applied Physics)