Longitudinal relaxation of muonium in Ge and GaAs

Longitudinal-field muon-spin depolarization rates in high-purityGe and semiinsulatingGaAs are reported and compared to similar data for intrinsicSi. Depolarization onset temperatures provide a comparison of charge carrier concentrations leading to rapid charge exchange and a shift in the onset, for n-typeGaAs verifies anelectron process. The temperature dependence of the low-field rate constants imply more complicated dynamics inGe than observed earlier inSi. Features near 750K inGaAsTe appear consistent with dissociation of aMu-Te pair.This work was supported by the US National Science Foundation (DMR-8917639 [TLE, BH]), the Science and Engineering Research Council of the UK (EAD, AS, SFJC), the Robert A. Welch Foundation (D-1053 [RLL], and C-1048 [TLE]), and a NATO Collaborative Research Grant (RLL, SFJC, RCD, CS). We wish to thank D.A. Vanderwater of Hewlett Packard for providing theGaAsTe sample.     

Production of helium fragments in197Au-emulsion collisions at 10.6 A GeV

We present a systematic analysis on the helium projectile fragments produced from 10.6 A GeV¹⁹⁷Auemulsion interactions in an experiment conducted at the Brookhaven AGS. Total charge changing and partial production cross-sections are measured experimentally on the basis of helium multiplicity. The multiplicity distribution of helium fragments which are produced collectively obey a KNO scaling. The transverse momentum distribution of these particles indicates that they are produced from two different independent sources.We are thankful to the BNL technical staff and specially to Dr. D. Beavis for his help in the exposure of emulsion stacks. Thanks are due to Profs. Y. Takahashi and G. Romano for their help in the preparation and development of the emulsion stacks. We appreciate the discussions with Prof. H. Stocker and J. Aichelin. This work was supported by D.O.E. under Grant No. DE-FGO2-90ER 40566.     

E.s.r. studies on acylhydrazine and hydrazone copper(II) sulfate complexes

Summary Cu^II complexes of the [CuL₂(SO₄)]·nH₂O and [CuL(SO₄)(H₂O)₂]·nH₂O type, where L = benzoylhydrazine (PhCONHNH₂; BH) or iso-propanone benzoylhydrazone (PhCONHN:CMe₂; IBH), L= iso-nicotinoylhydrazine (NC₅H₄CONHNH₂; INH) or isopropanone iso-nicotinoylhydrazone (NC₅H₄CONHN: CMe₂; IINH); n = 0–2, were prepared and characterized by elemental analyses, molar conductances, and electronic, e.s.r. and i.r. spectral measurements. The electronic and e.s.r. spectra suggest a tetragonally distorted octahedral geometry in the solid state as well as in DMSO solution. The e.s.r. data also reveal an axial symmetry for most of the complexes in the solid state and in DMSO solution at 300 and 77 K, while the complex of IBH is isotropic at 300 K. The M_s = 2 transition observed for this complex suggests that it is a dimer. BH and INH bond to Cu^II through the C-O and NH₂ groups, whereas IBH and IINH bond through C-O and C-N groups.