Author: Martin U. Schmidt

Production of charged pions, kaons, and (anti-)protons in Pb-Pb and inelastic pp collisions at sNN=5.02 TeV

Mid-rapidity production of $\pi^{\pm}$, $\rm{K}^{\pm}$ and ($\bar{\rm{p}}$)p measured by the ALICE experiment at the LHC, in Pb-Pb and inelastic pp collisions at $\sqrt{s_{\rm{NN}}}$ = 5.02 TeV, is presented. The invariant yields are measured over a wide transverse momentum ($p_{\rm{T}}$) range from hundreds of MeV/$c$ up to 20 GeV/$c$. The results in Pb-Pb collisions are presented as a function of the collision centrality, in the range 0$-$90%. The comparison of the $p_{\rm{T}}$-integrated particle ratios, i.e. proton-to-pion (p/$\pi$) and kaon-to-pion (K/$\pi$) ratios, with similar measurements in Pb-Pb collisions at $\sqrt{s_{\rm{NN}}}$ = 2.76 TeV show no significant energy dependence. B…

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Disordered sodium alkoxides from powder data: crystal structures of sodium ethoxide, propoxide, butoxide and pentoxide, and some of their solvates

The crystal structures of NaOEt, NaOPr, NaOBu and NaOAm (Am = amyl = pentyl) were determined from powder data. These compounds crystallize in an anti-PbO structure in the space groups P 21 m and P4/nmm. Additionally, solvates with the composition NaOEt·2EtOH, NaOPr·2PrOH, NaOiPr·5iPrOH and NaOtAm·tAmOH were synthesized, and their structures were determined from single crystals. They form interesting chain structures of different compositions and topologies.

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Using Electron Diffraction to Solve the Crystal Structure of a Laked Azo Pigment

The structure of the ζ phase of Pigment Red 53:2 was solved using electron diffraction data. The unit cell determination appeared to be more complicated due to twinning of the crystals. A series of...

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Λc+ Production and Baryon-to-Meson Ratios in pp and p -Pb Collisions at sNN=5.02 TeV at the LHC

The prompt production of the charm baryon Λ c + and the Λ c + / D 0 production ratios were measured at midrapidity with the ALICE detector in p p and p -Pb collisions at s NN = 5.02 TeV . These new measurements show a clear decrease of the Λ c + / D 0 ratio with increasing transverse momentum ( p T ) in both collision systems in the range 2 p T 12 GeV / c , exhibiting similarities with the light-flavor baryon-to-meson ratios p / π and Λ / K S 0 . At low p T , predictions that include additional color-reconnection mechanisms beyond the leading-color approximation, assume the existence of additional higher-mass charm-baryon states, or include hadronization via coalescence can describe the dat…

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Electron diffraction, X-ray powder diffraction and pair-distribution-function analyses to determine the crystal structures of Pigment Yellow 213, C23H21N5O9.

The crystal structure of the nanocrystalline alpha phase of Pigment Yellow 213 (P.Y. 213) was solved by a combination of single-crystal electron diffraction and X-ray powder diffraction, despite the poor crystallinity of the material. The molecules form an efficient dense packing, which explains the observed insolubility and weather fastness of the pigment. The pair-distribution function (PDF) of the alpha phase is consistent with the determined crystal structure. The beta phase of P.Y. 213 shows even lower crystal quality, so extracting any structural information directly from the diffraction data is not possible. PDF analysis indicates the beta phase to have a columnar structure with a si…

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Total-scattering pair-distribution function of organic material from powder electron diffraction data.

AbstractThis paper shows that pair-distribution function (PDF) analyses can be carried out on organic and organometallic compounds from powder electron diffraction data. Different experimental setups are demonstrated, including selected area electron diffraction and nanodiffraction in transmission electron microscopy or nanodiffraction in scanning transmission electron microscopy modes. The methods were demonstrated on organometallic complexes (chlorinated and unchlorinated copper phthalocyanine) and on purely organic compounds (quinacridone). The PDF curves from powder electron diffraction data, called ePDF, are in good agreement with PDF curves determined from X-ray powder data demonstrat…

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Crystal structure of disordered nanocrystalline $\alpha^{II}$-quinacridone determined by electron diffraction

CrystEngComm 18(4), 529 - 535(2016). doi:10.1039/C5CE01855B

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Measurements of inclusive jet spectra in pp and central Pb-Pb collisions at sNN=5.02TeV

This article reports measurements of the pT- differential inclusive jet cross section in pp collisions at √s=5 .02TeV and the pT- differential inclusive jet yield in Pb-Pb 0–10% central collisions at√sNN =5.02TeV. Jets were reconstructed at midrapidity with the ALICE tracking detectors and electromagnetic calorimeter using the anti-kT algorithm. For ppcollisions, we report jet cross sections for jet resolution parameters R =0.1–0.6 over the range 20 < pT, jet < 140 GeV/c, as well as the jet cross-section ratios of different R and comparisons to two next-to-leading-order (NLO)– based theoretical predictions. For Pb-Pb collisions, we report the R=0.2 and R=0.4 jet spectra for 40 < pT, jet < 1…

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Crystal Structures and Polymorphism of Nickel and Copper Coordination Polymers with Pyridine Ligands

The crystal structures of a series of pyridine coordination polymers [MIICl2(C5H5N)x]n (M = Ni, Cu), prepared via thermal decomposition are reported. [NiCl2(C5H5N)4] (1) decomposes stepwise via [NiCl2(C5H5N)2]n (2), [NiCl2(C5H5N)]n (3), and [NiCl2(C5H5N)2/3]n (4), to NiCl2 with increasing temperature. The thermal decomposition of [CuCl2(C5H5N)2]n (5), progresses via two polymorphs of [CuCl2(C5H5N)]n (6a and 6b), and [CuCl2(C5H5N)2/3]n (7), to CuCl2. The compounds 3, 4, and 7 were prepared as pure phases. All crystal structures were determined by X-ray powder diffraction. Notably, the crystal structures of the polymorphs 6a and 6b were determined from powder diffraction data of a mixture of …

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CCDC 1943794: Experimental Crystal Structure Determination

Related Article: F. Sabbaghi, A. As'habi, A. Saneei, M. Pourayoubi, A.A. Abdul Salam, M. Nečas, M. Dušek, M. Kučeráková, S. Acharya|2021|Acta Crystallogr.,Sect.C:Cryst.Struct.Chem.|77|68|doi:10.1107/S2053229620016502

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