Relativity from Light Front and Bethe–Salpeter Equations

We present some results of two independent relativistic approaches to the few-body problem: light-front dynamics and Bethe–Salpeter equation. We show that implementing relativistic invariance leads to new qualitative properties, and that, even driven by the same interaction Lagrangian, both approaches provide different quantitative results, especially in three-body systems. The case of Bethe–Salpeter equation for computing electromagnetic form factors is discussed.     

NMR Studies of Agricultural Compounds. Applications of Achiral and Chiral Lanthanide Shift Reagents to the Herbicide,Diclofop Methyl

The 60 MHz H NMR spectra for the herbicide, diclofop methyl, 1, have been studied in CDCl₃ solution at 28±1° with the added achiral lanthanide shift reagent (LSR) tris (6,6,7,7,8,8,8-heptafluoro-2,2-dimethyl-3,5-octanedionato) europium(III), Eu (FOD)₃, 2, and with the chiral LSRs, tris[3-(heptafluoropropylhydroxymethylene)-(+)-camphorato]europium(III)₃, Eu(HFC)₃, 3, and tris[3-(trifluoromethylhydroxymethylene)-(+)-camphorato]europium(III), Eu(FACAM)₃, 4. Both 2 and 3 produced substantial lanthanide-induced shifts (LIS) consistent with predominant LSR binding at the ester carbonyl. Much smaller LIS magnitudes were observed with 4. Modest enantiomeric shift differences (ΔΔδ) were elicited with 3 for the OCH₃ and the CCH₃ resonances of 1. The former signal appears to offer greatest potential for the direct determination of enantiomeric excess of samples of 1, with 3:1 molar ratios ca. 0.3–0.4 resulting in valley heights as low as 33% of the average peak heights of the OCH₃ signals of the two enantiomers.     

Time-dependent probability density of statistical mechanics

We study fluctuations around nonequilibrium steady states of some model nonlinear chemical systems. A previous result of Nicolis and Prigogine states that the mean square fluctuation computed from a master equation in the space of internal states of the reacting species is identical to that calculated from Einstein's fluctuation formula. Our analysis of fluctuations based on that master equation leads with the assumption of local equilibrium to a result identical to that obtained from a master equation for the total concentration of the reacting species, which is different from the equilibrium (Einstein relation) result. Nicolis and Prigogine approximated one term in their master equation, and a discussion of this approximation is presented. The master equation without this approximation yields at equilibrium the result expected on the basis of Einstein's formula.Work supported in part by the National Science Foundation and Project SQUID, Office of Naval Research.     

Panel Session on the Future of Few-Body Physics

During the 22nd European Few-Body Conference, a session was devoted to a panel discussion on the future of few-body physics. The panel members were Charlotte Elster, Jaume Carbonell, Evgeny Epelbaum, Nasser Kalantar-Nayestanaki, and Jean-Marc Richard. The session was chaired by Ben Bakker. After presentations by the panel members, several topics were discussed with the audience. The conclusions of this discussion are presented in this paper.     

Yukawa model on a lattice: Two-body states

We present some Quantum Field Theory (QFT) results concerning the Yukawa model, solved non-perturbatively with the help of lattice techniques. In particular we focus on the possibility of generating a two-nucleon bound state, as compared to the non-relativistic limit of the same model. Preliminary results show the appearance of zero modes of the Dirac operator. They limit the numerical solution of the model to values of the coupling constant which are too small to allow binding of the two-nucleon system.     

Annihilation of slow antiprotons in flight and in traps

The antiproton-nucleus annihilation in two possible experimental situations (low energy in-flight annihilation and annihilation in a trap) is investigated taking into account the Coulomb interaction. For these two cases, the formulas giving the relation between the antiproton-nucleus scattering lengtha _cs and observables (annihilation cross section and antiprotons time-of-life in a trap) are obtained. These relations are proposed to determinea _cs.     

Ultrathin film deposition by liquid CO2 free meniscus coating-uniformity and morphology

Ultrathin organic films of sucrose octaacetate (SOA) were deposited on 12.5 cm diameter silicon wafer substrates using high-pressure free meniscus coating (hFMC) with liquid CO2 (l-CO2) as a coating solvent. The dry film thickness across the wafer and the morphology of deposited films were characterized as a function of coating conditions-withdrawal velocity, solution concentration, and evaporation driving force (deltaP). When no evaporation driving force was applied (deltaP = 0), highly uniform films were deposited with thickness in the range of 8-105 angstroms over the entire concentration range (3-11 wt%). Uniform films were also obtained at low concentrations (3-5 wt%) with a low evaporation driving force (deltaP = 0.0138 MPa). However, films deposited at medium to high concentrations (7-11 wt%) were thicker (110-570 angstroms) and less uniform, with larger nonuniformities at higher applied evaporation driving forces. Optical microscopy and atomic force microscopy (AFM) were used to characterize film morphology including drying defects and film roughness. Films deposited without evaporation had no apparent drying defects and very low root-mean-square (RMS) roughness (1.4-3.8 angstroms). Spinodal-like dewetting morphologies including holes with diameters in the range of 100-300 nm, and surface undulations were observed in films deposited at medium concentration (7 wt%) and low deltaP (0.0138-0.0276 MPa). At higher concentrations and higher evaporative driving forces, spinodal-like dewetting morphologies disappeared but concentric ring defect structures were observed with diameters in the range 20-125 microm. The film thickness and morphology of SOA films deposited from 1-CO2 hFMC were compared to those deposited from toluene and acetone under normal dip coating. Films deposited from l-CO2 hFMC were much thinner, more uniform, and exhibited much fewer drying defects and lower RMS roughness.