Spin Representations,Powers of 2 and the Glaisher Map

Generalizing results on spin character degrees, we determine for a given conjugacy class of odd type in the double cover of S_n spin characters of S_n which have the minimal 2-power on this class in their character value. Surprisingly, the Glaisher map plays an important rôle here. Presented by L. Le BruynMathematics Subject Classifications (2000) 20C30, 05A15.     

Fission of232Th induced by 4–11 MeV protons

The excitation function for the²³²Th(p,f) reaction has been determined in the energy range from 4 to 11 MeV. A discrepancy existing in the literature is resolved. The mass yield distribution has been studied at 8 MeV proton energy and the peak-to-valley ratio has been determined to be 9.2. The fission data, together with evaporation residue data from an earlier experiment, are understood rather well within the framework of a statistical decay model which derives its parameters from independent data. The absorption cross sections for protons in the vicinity of and below the Coulomb barrier are also discussed and confronted with optical model predictions using published global proton potentials.     

Mass yields in the binary fission of Ag,La and Tb

The mass distributions from the binary fission of Ag, La and Tb induced by 600 MeV protons are presented. The experimental results are compared with the predictions of macroscopic theories, in particular the version of the liquid drop model including dynamical and statistical effects.     

Experimental set-up for irradiation of solid H2 and D2 with charged particles of keV energies

An experimental facility was built where films of solid deuterium (and hydrogen) may be made with known thickness and irradiated with pulsed beams of electrons (up to 3 keV) and light ions (up to 10 keV). Films are made on a target plate held at 2.5–3 K. Film growth rate is calibrated with a quartz crystal film thickness monitor. The target plate, which can be heated so that films are removable by evaporation, may be used both as a calorimeter and as a beam current collector. Methods for measurement of secondary electron emission coefficients were developed, and preliminary measurements were made with electrons and hydrogen ions. For electron bombardment, the secondary electron emission coefficient of solid deuterium was much smaller than one. It was shown possible to use the set-up to study beam desorption of very thin films. Furthermore the set-up could be used for measuring the energy-reflection coefficient γ (i.e. the fraction of beam energy reflected from the target) for protons impinging on a heavy target material by using the target as a calorimeter.     

Production and microwave spectra of dithioformic acid,HCSSH

Hitherto unknown dithioformic acid, HCSSH, has been produced by pyrolysis (300°C) of methanetrithiol, HC(SH)₃, and identified by the microwave spectrum (18–40 GHz) of its most abundant species H¹²C³²S³²SH. Rotational transitions of this species in its ground state have been assigned to a trans and a cis rotamer. Both rotamers are planar, the trans conformer being the more stable by ca. 350 cm^?1 mole^?1. For each rotamer spectra of molecules in two vibrationally excited states have been assigned. Frequencies of transitions of importance for search for HCSSH in interstellar space are reported.     

Copper(II), lead and zinc complexes of ethylenediamine-N,N'-diacetic acid

From potentiometric measurements with glass and ion-specific electrodes, the formation constants of the complexes of ethylenediamine-N,N'-diacetic acid (EDDA, H(2)X) and Cu(2+), Pb(2+) and Zn(2+) have been determined at 25.0 degrees and ionic strength of 0.1 (NaNo(3)). The formation constants of the protonated species of EDDA were determined from separate measurements. The following species and log beta values were found (standard deviations in parentheses): HX(-) 9.17 (0.03); H(2)X 6.36 (0.02), H(3)X(+) 1.54 (0.16); CuX 17.47 (0.02); CuHX 20.87 (0.05); Cu(OH)X 6.34 (0.05); Cu(2)X 20.85 (0.14); PbX 11.71 (0.01); PbHX 15.60 (0.02); PbOHX 12.27 (0.02); Pb(2)X 15.02 (0.01); ZnX 11.71 (0.01); ZnHX 15.48 (0.03); Zn(OH)X 11.98 (0.03); Zn(2)X 14.91 (0.01). (Stepwise constants are given for HX(-), H(2)X and H(3)X(+).).     

Palladium-promoted asymetric oxyamination of alkenes application to the synthesis of optically active aryloxypropanolamines

Palladium-promoted oxyamination of some alkene using optically active N-methyl-α?enylethylamine as amine nucleophile, or using optically active N,N-dimethyl-α-phenylethylamine as ligand, produces optically active aminoalcohol derivatives in an optically yield of 3–60%. Oxyamination of aryl ethers gives optically active 1-amino-3-aryloxy-propan-2-ol derivatives, which are important β-blockers.     

Fission induced by heavy-ion collisions

Fission fragment angular distributions from sequential fission induced in heavy-ion reactions will depend on the angular momentum exchange occuring in such reactions in considerable detail. Theoretical expressions for the angular distributions of fission products from totally and partly polarized nuclei are presented. They are compared with recent measurements and discussed in relation to the deep inelastic reaction mechanism.