Feshbach resonances in the 6Li-40K Fermi-Fermi mixture: elastic versus inelastic interactions

We present a detailed theoretical and experimental study of Feshbach resonances in the ⁶Li-⁴⁰K mixture. Particular attention is given to the inelastic scattering properties, which have not been considered before. As an important example, we thoroughly investigate both elastic and inelastic scattering properties of a resonance that occurs near 155?G. Our theoretical predictions based on a coupled channels calculation are found in excellent agreement with the experimental results. We also present theoretical results on the molecular state that underlies the 155?G resonance, in particular concerning its lifetime against spontaneous dissociation. We then present a survey of resonances in the system, fully characterizing the corresponding elastic and inelastic scattering properties. This provides the essential information to identify optimum resonances for applications relying on interaction control in this Fermi-Fermi mixture.     

Laser heating versus phonon confinement effect in the Raman spectra of diamond nanoparticles

In this study, PbSe nanocubes were obtained by high-energy milling, and their optical properties were investigated by measuring the UV?CVIS?CIR spectra in the range of 200?C2,000?nm. The optical absorption of all samples showed a strong UV emission band at 1.45?eV. Previously, to obtain only PbSe nanocubes, an intermediate phase was identified, PbSeO₃. Although both PbSeO₃ and PbSe were traced through this study, a major effort is devoted to characterize the latter. To trace how chemical transitions evolve from precursors to PbSe, X-ray diffraction and Rietveld refinement were carried out. Therefore, the following parameters were evaluated as a function of milling time: phase percentages, area-to-volume ratio, average crystallite dimensions, specific surface area, and morphology changes. To corroborate previous findings, nitrogen adsorption and transmission electron microscopy techniques were used. All the set experimental results unambiguously confirm that crystallites show a cubic morphology, with its average crystallite size distribution being around 24?nm.     

Creation of a dipolar superfluid in optical lattices

We show that, by loading a Bose-Einstein condensate of two different atomic species into an optical lattice, it is possible to achieve a Mott-insulator phase with exactly one atom of each species per lattice site. A subsequent photoassociation leads to the formation of one heteronuclear molecule with a large electric dipole moment, at each lattice site. The melting of such a dipolar Mott insulator creates a dipolar superfluid, and eventually a dipolar molecular condensate.     

Ultracold collision properties of metastable alkaline-earth atoms

Ultracold collisions of spin-polarized 24Mg, 40Ca, and 88Sr in the metastable 3P2 excited state are investigated based on molecular potentials obtained from ab initio calculations. We calculate the long-range interaction potentials and estimate the scattering length and the collisional loss rate as a function of magnetic field. The scattering lengths show resonance behavior due to the appearance of a molecular bound state in a purely long-range interaction potential and are positive for magnetic fields below 50 mT. A loss-rate model shows that losses should be smallest near zero magnetic field and for fields slightly larger than the resonance field, where the scattering length is also positive.     

Synthesis of Thiadiazolylaminoglycosides Through Ring Contraction of Triazinoglycosides Induced by [TBA‐Ox]

A new synthetic route to thiadiazolylaminoglycosides, by a ring expansion/ring contraction sequence of glycosyl triazines, has been developed. Two potential mechanisms of this oxidative ring contraction using [TBA‐Ox] are discussed. The more plausible involves formation of an oxatriazepane intermediate followed by loss of formic acid, ring opening, and subsequent recyclization.     

Determination of N,N'-ethylenebisstearamide additive in polymer by normal phase liquid chromatography with evaporative light scattering detection

A new method for N,N'-ethylenebisstearamide (EBS) analysis was developed and validated in normal phase-HP liquid chromatography (NP-HPLC) with diol column at 50 degrees C with 100% CHCl(3) at 1 mL min(-1) and evaporative light scattering detection with elution time at 3.0 min. EBS solubility was the best at 0.80 gL(-1) in CHCl(3)/methanol 90:10. The molecular structure of commercial samples of EBS was determined by GC-MS which ascertained that the main structure is C18/C18 at approximately 45%. The remaining part was constituted by molecules with different alkyl chain length. The HPLC quantification method was proved linear (r=0.9983), accurate (99.6%) and precise (1.95%). Limit of quantification (LOQ) and limit of detection (LOD) were equal to 2.0 and 0.8 microg mL(-1), respectively. The suitability of this method was assessed with a dissolution/precipitation extraction procedure of EBS from ethylene vinyl acetate (EVA) polymer which showed that other additives and polymer do not interfere with EBS analysis. The intra-day and day-to-day precisions of extraction method were equal to 9.1% and 9.9%, respectively.     

Universal ultracold collision rates for polar molecules of two alkali-metal atoms

Universal collision rate constants are calculated for ultracold collisions of two like bosonic or fermionic heteronuclear alkali-metal dimers involving the species Li, Na, K, Rb, or Cs. Universal collisions are those for which the short range probability of a reactive or quenching collision is unity such that a collision removes a pair of molecules from the sample. In this case, the collision rates are determined by universal quantum dynamics at very long range compared to the chemical bond length. We calculate the universal rate constants for reaction of the reactive dimers in their ground vibrational state v = 0 and for vibrational quenching of non-reactive dimers with v ≥ 1. Using the known dipole moments and estimated van der Waals coefficients of each species, we calculate electric field dependent loss rate constants for collisions of molecules tightly confined to quasi-two-dimensional geometry by a one-dimensional optical lattice. A simple scaling relation of the quasi-two-dimensional loss rate constants with dipole strength, trap frequency and collision energy is given for like bosons or like fermions. It should be possible to stabilize ultracold dimers of any of these species against destructive collisions by confining them in a lattice and orienting them with an electric field of less than 20 kV cm(-1).     

Ferrocene‐substituted 3,3′‐diindolylmethanes with improved anticancer activity

A series of ferrocene‐substituted derivatives ( 2a , 2b , 2c , 2d , 2e , 2f , 2g ) of the known drug 3,3′‐diindolylmethane ( DIM ) were prepared and tested for their in vitro antitumor activity. The derivatives 2a (featuring indole moiety), 2b (featuring 2‐methylindole moiety) and 2f (featuring 5‐nitroindole moiety) were growth‐inhibiting in vitro at lower concentrations than DIM in various tumor cells including pancreas cancer (BcPC‐3), three DIM‐resistant cancer cell lines (518 A2, KB‐V1/Vbl, HT‐29), triple‐negative breast cancer (MDA‐MB‐231) and prostate cancer (PC‐3). Derivatives 2a , 2b and 2f were the most active compounds of this series, qualifying as drug candidates for various cancer diseases. Copyright © 2016 John Wiley & Sons, Ltd.     

Universality of the three-body parameter for Efimov states in ultracold cesium

We report on the observation of triatomic Efimov resonances in an ultracold gas of cesium atoms. Exploiting the wide tunability of interactions resulting from three broad Feshbach resonances in the same spin channel, we measure magnetic-field dependent three-body recombination loss. The positions of the loss resonances yield corresponding values for the three-body parameter, which in universal few-body physics is required to describe three-body phenomena and, in particular, to fix the spectrum of Efimov states. Our observations show a robust universal behavior with a three-body parameter that stays essentially constant.