Molecular Lanthanide Switches for Magnetism and Photoluminescence

Solvation of [(CNT)Ln(η⁸-COT)] (Ln=La, Ce, Nd, Tb, Er; CNT=cyclononatetraenyl, i.e., C₉H₉⁻; COT=cyclooctatetraendiid, i.e., C₈H₈²⁻) complexes with tetrahydrofuran (THF) gives rise to neutral [(η⁴-CNT)Ln(thf)₂(η⁸-COT)] (Ln=La, Ce) and ionic [Ln(thf)_x(η⁸-COT)][CNT] (x=4 (Ce, Nd, Tb), 3 (Er)) species in a solid-to-solid transformation. Due to the severe distortion of the ligand sphere upon solvation, these species act as switchable luminophores and single-molecule magnets. The desolvation of the coordinated solvents can be triggered by applying a dynamic vacuum, as well as a temperature gradient stimulus. Raman spectroscopic investigations revealed fast and fully reversible solvation and desolvation processes. Moreover, we also show that a Nd:YAG laser can induce the necessary temperature gradient for a self-sufficient switching process of the Ce(III) analogue in a spatially resolved manner.     

Evaluation of charged current neutrino–nucleon interaction differential cross section

The charged current neutrino–nucleon interaction differential cross section are evaluated in the kinematical range 30<Eν<300 GeV$30<E_{\nu }<300\text{GeV}$, 0.1<x<0.8$0.1<x<0.8$ and 0<y<1$0<y<1$ using QCD inspired Thermodynamic Bag Model (TBM). We also discuss the x   and Q²$Q^2$ dependence of nucleon structure functions F₂(x,Q²)$F_2(x,Q^2)$ and xF₃(x,Q²)$x{F}_3(x,Q^2)$ estimated with statistical approach. The contribution of strange quark distribution function to the cross section is explored and the results obtained have been compared with relevant data from NuTeV and CHORUS experiments.     

Graviton plus vector boson production to NLO in QCD at the LHC

We present the next-to-leading order QCD corrections to the associated production of the vector gauge boson (Z/W^±$Z/W^{\pm }$) and the graviton in the large extra dimension model at the LHC. We estimate the impact of the QCD corrections on the total cross sections as well as the differential distributions of the gauge bosons and find that they are significant. We also study the dependence of the cross sections on the arbitrary factorization scale and show the reduction in the scale uncertainties at NLO level. Further, we discuss the ultraviolet sensitivity of the theoretical predictions.     

Selective colorimetric sensing of cysteine in aqueous solutions using silver nanoparticles in the presence of Cr³+

We here in report an extensive study on the development of a highly facile, selective and sensitive colorimetric probe for cysteine detection using silver nanoparticles (Ag NPs). The efficacy of the process relies upon the surface plasmon resonance properties of Ag NPs and the interaction of Ag-cysteine complex with chromium ions (Cr³⁺) in a ratio of 2:1. In the presence of Cr³⁺, cysteine was able to induce the aggregation of Ag NPs thereby resulting in a change in yellow colour of the Ag colloid to purple. The reported probe has a limit of detection down to 1 nM which is to the best of our knowledge the lowest ever reported for the colorimetric detection of cysteine. Furthermore, a remarkable feature of this method is that it involves a simple technique exhibiting high selectivity to cysteine over other tested amino acids.     

The growth and characterization of a metal organic crystal, potassium thiourea thiocyanide

The growth and characterization of a new non-linear organometallic crystal, potassium thiourea thiocyanide (PTT) is reported. The growth of single crystals was accomplished by the slow evaporation solution growth method. The grown crystals were characterized by XRD, TG–DTA, UV, and FTIR spectral analyses. PTT has good optical transmission in the entire visible region which is an essential requirement for a non-linear crystal. TG curve of PTT undergoes complete decomposition between 176 and 1,000 °C in three steps with corresponding three DTA peaks. The high thermal stability of organometallic crystals are due to strong bonding existing between the conjugation layers of thiourea molecule and the potassium ions.     

Evolution of disorder in Zn(CN)2 at high pressure

Zinc cyanide is an interesting negative thermal expansion (NTE) material exhibiting cubic structure at ambient pressure and temperature. We have investigated the structural stability of zinc cyanide under high pressure up to 5.2 GPa by performing X-ray powder diffraction in a diamond anvil cell. Under very low pressure of about 0.6 GPa, the diffraction peaks drastically reduce in intensity, indicating possible onset of disorder in the structure. In this paper, its high pressure structural and compressibility behaviour, bulk modulus and the pressure derivative of bulk modulus are reported.     

Diphoton signals in theories with large extra dimensions to NLO QCD at hadron colliders

We present a full next-to-leading order (NLO) QCD corrections to diphoton production at the hadron colliders in both standard model and ADD model. The invariant mass and rapidity distributions of the diphotons are obtained using a semi-analytical two cut-off phase space slicing method which allows for a successful numerical implementation of various kinematical cuts used in the experiments. The fragmentation photons are systematically removed using smooth-cone-isolation cuts on the photons. The NLO QCD corrections not only stabilise the perturbative predictions but also enhance the production cross section significantly.     

Digital detection and processing of multiple quadrature harmonics for EPR spectroscopy

A quadrature digital receiver and associated signal estimation procedure are reported for L-band electron paramagnetic resonance (EPR) spectroscopy. The approach provides simultaneous acquisition and joint processing of multiple harmonics in both in-phase and out-of-phase channels. The digital receiver, based on a high-speed dual-channel analog-to-digital converter, allows direct digital down-conversion with heterodyne processing using digital capture of the microwave reference signal. Thus, the receiver avoids noise and nonlinearity associated with analog mixers. Also, the architecture allows for low-Q anti-alias filtering and does not require the sampling frequency to be time-locked to the microwave reference. A noise model applicable for arbitrary contributions of oscillator phase noise is presented, and a corresponding maximum-likelihood estimator of unknown parameters is also reported. The signal processing is applicable for Lorentzian lineshape under nonsaturating conditions. The estimation is carried out using a convergent iterative algorithm capable of jointly processing the in-phase and out-of-phase data in the presence of phase noise and unknown microwave phase. Cramér-Rao bound analysis and simulation results demonstrate a significant reduction in linewidth estimation error using quadrature detection, for both low and high values of phase noise. EPR spectroscopic data are also reported for illustration.     

Crystal and molecular structure of tetra-n-butylammoniumbis(stilbenedithiolato)-nickelate(III)

The crystal and molecular structure of the title compound, C₄₄H₅₆NS₄Ni, are reported. Crystals are triclinic, space groupP¯1 (No. 2) withZ=2 in a unit cell of dimensionsa=8.874(2) Å,b=9.549(5) Å,c=26.025(7) Å,=97.22(3)°,=95.06(2)°, and=98.75(3)°. The structure was solved by Patterson and Fourier methods and refined by full-matrix least squares toR=0.062 for 2910 unique diffractometer data. The metal atom of the anion has an approximate square-planar configuration and the nitrogen atom of the cation an approximate tetrahedral configuration. The anions as well as the cations are well separated, the closest NiNi and NN approaches being the lattice repeat of 8.874(2) Å.     

Error analysis for Galerkin POD approximation of the nonstationary Boussinesq equations

In this article, we study error estimates for approximate solutions of POD Galerkin type for the equations for the motion of a nonstationary viscous thermally conducting fluid in a bounded domain. Time discretization is based on backward Euler scheme. We study both the fully implicit and semi‐implicit versions of this scheme. © 2010 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq 27 : 1639‐1665, 2011