The light CP-even MSSM Higgs mass resummed to fourth logarithmic order

We present the calculation of the light neutral CP-even Higgs mass in the MSSM for a heavy SUSY spectrum by resumming enhanced terms through fourth logarithmic order (N\(^{3}\)LL), keeping terms of leading order in the top Yukawa coupling \(\alpha _t\), and NNLO in the strong coupling \(\alpha _s\). To this goal, the three-loop matching coefficient for the quartic Higgs coupling of the SM to the MSSM is derived to order \(\alpha _t^2\alpha _s^2\) by comparing the perturbative EFT to the fixed-order expression for the Higgs mass. The new matching coefficient is made available through an updated version of the program Himalaya. Numerical effects of the higher-order resummation are studied using specific examples, and sources of theoretical uncertainty on this result are discussed.     

Hydrogel microspheres: influence of chemical composition on surface morphology, local elastic properties, and bulk mechanical characteristics

Hydrogel microspheres, beads, and capsules of uniform size, differing in their chemical composition, have been prepared by electrostatic complex formation of sodium alginate with divalent cations and polycations. These have served as model spheres to study the influence of the chemical composition on both surface characteristics and bulk mechanical properties. Resistance to compression experiments yielding the compression work clearly identified differences as a function of the composition, with forces at maximal compression in the range of 34-455 mN. The suitability and informative value of atomic force microscopy have been confirmed for the case where surface characterization is performed in a liquid environment equivalent to physiological conditions. Surface imaging and mechanical response to indentation revealed different average surface roughness and Young's moduli for all hydrogel types ranging from 0.9 to 14.4 nm and from 0.4 to 440 kPa, respectively. The hydrogels exhibited pure elastic behavior. Despite a relatively high standard deviation, resulting from both surface and batch heterogeneity, nonoverlapping ranges of Young's moduli were reproducibly identified for the selected model spheres. The findings indicate the reliability of contact mode atomic force microscopy to quantify local surface properties, which may have an impact on the biocompatibility of alginate-based hydrogel materials of different composition and conditions of preparation. Moreover, it seems that local elastic properties and bulk mechanical characteristics are subject to analogous composition influences.     

Electrical Conductivity and Strong Luminescence in Copper Iodide Double Chains with Isonicotinato Derivatives

Direct reactions between CuI and isonicotinic acid (HIN) or the corresponding esters, ethyl isonicotinate (EtIN) or methyl isonicotinate (MeIN), give rise to the formation of the coordination polymers [CuI(L)]_n with L=EtIN ( 1 ), MeIN ( 2 ) and HIN ( 3 ). Polymers 1 – 3 show similar structures based on a CuI double chain in which ethyl‐, methyl isonicotinate or isonicotinic acid are coordinated as terminal ligands. Albeit, their supramolecular architecture differs considerably, affecting the distances and angles of the central CuI double chains and thereby their physical properties. Hence, the photoluminescence shows remarkable differences; 1 and 2 show a strong yellow emission, whereas 3 displays a weak emission; and 1 and 2 are semiconductors with moderate room temperature conductivities, whereas 3 has increased electrical conductivity up to 3×10^?3 S cm^?1. Additionally, 1 and 2 present an irreversible transition to a highly conducting phase with a conductivity almost 4 orders of magnitude higher and a quasi‐metallic behaviour. Thermogravimetric analysis (TGA) coupled to a mass spectrometer and magnetic measurements point to a partial thermally induced oxidation of the carboxylate groups of the ligands with Cu^I to Cu⁰ reduction. DFT calculations have been carried out to rationalise these observations.     

Synthesis, crystal structure and molecular modeling (AM1) of two 5-arylidene derivatives of Meldrum's acid

The synthesis and structural characterization of two 5-Arylidene derivatives of Meldrum's acid (2,2-dimethyl-1,3-dioxane-4,6-dione) are described: 5-(4-Nitrobenciliden)-2,2-dimethyl-1,3-dioxane-4,6-dione (3a), and 5-(4-Methoxybenciliden)-2,2-dimethyl-1,3-dioxane-4,6-dione (3b). The structure of 3a was refined to R₁ = 0.0421 for 2148 reflections (with I > 2 (I)). Crystal data for 3a: C₁₃H₁₁NO₆, orthorhombic, space group Pbca, a = 16.008(3), b = 6.137(1), c = 25.281(5) Å, V = 2483.6(8) ų, Z = 8. The structure of 3b was refined to R₁ = 0.0496 for 4681 reflections (with I > 2(I)). Crystal data for 3b: C₁₄H₁₄O₅, triclinic, space group P1, a = 9.131(2), b = 9.922(2), c = 14.490(3)Å, = 85.076(6), = 84.80(3), = 89.37(2)°,V = 1302.4(5) ų, Z = 4. The results of crystallographic and molecular modeling (AM1) were compared. The molecules in the crystal are held together, in both compounds, by van der Waals forces and C—H···O hydrogen bond interactions.     

Electronic and magnetic properties of (tetrakis(2‐pyridylmethyl)‐ ethylenediamine)iron(II) perchlorate. A comparison of different computational methods

Based on the X‐ray diffraction data, electronic and magnetic properties of the (tetrakis(2‐pyridylmethyl)ethylenediamine)iron(II) perchlorate complex have been studied using three different unrestricted computational methods. The changes of energy versus temperature obtained by different computational methods are compared. The extent of spin contaminant and its influence on the energy, the spin, the charge populations, and the characteristics of molecular orbitals are analyzed in detail. Comparison of the computational results and spin‐state transition phenomena of this complex demonstrates that the B3LYP method is the most satisfactory, leading to an excellent correlation with experimental data. © 2001 John Wiley & Sons, Inc. Int J Quant Chem 83: 60–69, 2001     

Controlling transformations in the assembly of polyoxometalate clusters: {Mo11V7}, {Mo17V8} and {Mo72V30}

The reaction of molybdate with vanadium(V) in the presence of sulfite anions is explored showing how, via cation control, stepwise assembly through the {Mo(11)V(7)} cluster yields a {M(25)} cluster-based compound, [Mo(VI)(11)V(V)(5)V(IV)(2)O(52)(μ(9)-SO(3))(Mo(VI)(6)V(V)O(22))](10-) (1a), which was first discovered using cryospray mass spectrometry, whereas switching the cation away from ammonium allows the direct formation of the spherical 'Keplerate' {Mo(72)V(30)} cluster.     

Limits on charge carrier mobility in suspended graphene due to flexural phonons

The temperature dependence of the mobility in suspended graphene samples is investigated. In clean samples, flexural phonons become the leading scattering mechanism at temperature T?10 K, and the resistivity increases quadratically with T. Flexural phonons limit the intrinsic mobility down to a few m(2)/V s at room T. Their effect can be eliminated by applying strain or placing graphene on a substrate.     

Regioselective synthesis of fluoroalkylated beta-aminophosphorus derivatives and aziridines from phosphorylated oximes and nucleophilic reagents

A simple and efficient stereoselective synthesis of fluoroalkyl substituted aziridine-2-phosphine oxides and -phosphonates by diastereoselective addition of methoxide, imidazole, benzenethiol, and Grignard reagents to functionalized ketoxime-phosphine oxides and -phosphonates is described. Aziridines are used as intermediates for the regioselective synthesis of fluorine containing beta-amino phosphine oxides and beta-amino phosphonates. Amino phosphorus derivatives can also be obtained from ketoximes derived from phosphine oxides and phosphonates with sodium borohydride.