Table of contents

Differential cross sections for the reaction ¹²C(p,³He)¹⁰B at 185 MeV have been measured in the angular region 4° to 20°. The momentum analysis of the ³He particles was performed in a magnetic spectrometer. A spark chamber with current distribution read-out was used as a detector, and it was triggered by pulses from a scintillation telescope. An overall energy resolution of about 350 keV was obtained in the energy spectra. The angular distributions of the cross section were all peaked in the forward direction.

The structures of ⁵⁵Mn, ⁵⁵Fe and ⁵⁷Fe have been investigated by coincidence, yield, angular distribution, and linear polarization measurements of gamma-ray decay from alpha-induced reactions on ⁵²Cr and ⁵⁴Cr at Eα = 14.2 MeV. Several high-spin states are assigned: In ⁵⁵Mn 984 keV 9/2^-, 1 291 keV 11/2^- (both confirmed) and 2 309 keV 13/2^-; in ⁵⁵Fe 931 keV 5/2^-, 1 316 keV 7/2^-, 1 408 keV 7/2^-, 2 211 keV 9/2^- 2 300 keV 9/2^-, 2 539 keV 11/2^- (all six confirmed) and 2 814 keV 13/2^(-), 2 982 keV 11/2^(-), 3 071 keV 11/2^-, 3 419 keV 15/2^(-) and 3 456 keV (tentative 13/2^-); in ⁵⁷Fe 316 keV 3/2^-, 706 keV 5/2^- (both confirmed) and 1 007 keV 7/2^-, 1 197 keV 9/2^-, 1 357 keV 3/2^(-), 1 989 keV 9/2^(-), 2 355 keV 11/2^-, 2 455 keV 9/2^-, 2 879 keV 13/2^-, 3 135 keV 15/2^(-), 3 268 keV 13/2^(-) and 4 429 keV, 4 524 keV (spins undetermined).

The magnetic dipole and the electric quadrupole interaction constants a and b have been measured for the neutron-deficient dysprosium isotopes ¹⁵³Dy (6 h), ¹⁵⁵Dy (10 h) and ¹⁵⁷Dy (8.1 h) using the atomic-beam magnetic resonance method. The results are

¹⁵⁷Dy |a| = 121.605 (4) MHz |b| = 564.65 (7) MHz b/a< 0

¹⁵⁵Dy |a| = 136.5 (5) MHz |b| = 421 (5) MHz b/a<0

¹⁵³Dy |a| = 123.5 (8) MHz |b| = 65 (40) MHz b/a>0

For the evaluation of the corresponding nuclear moments of these isotopes a theoretical analysis of the hyperfine structure has been performed using an effective hyperfine structure Hamiltonian within the 4f¹⁰ configuration. The values of ⟨r^-3⟩ needed for the calculation have been obtained using relativistic self-consistent-field wavefunctions. The analysis yields the following nuclear moments:

¹⁵⁷Dy: μ_I = -0.30 (3) n.m. Q = +1.22 (13) barn

¹⁵⁵Dy: μ_I = -0.34 (3) n.m. Q = +0.91 (10) barn

¹⁵³Dy: μ_I = -0.71 (9) n.m. Q = -0.14 (8) barn

The quadrupole moments are corrected for the Sternheimer effect. A comparison with recent moment calculations using the unified nuclear model is made.

An analysis of the magnetic and electric hyperfine structure has been performed for the 6p³ configuration of ²⁰⁹Bi by use of an effective hyperfine structure Hamiltonian. For the magnetic hyperfine structure, experimental mean values of r^-3 exist for the orbital, spin-dipole and spin terms of the Hamiltonian. Theoretical mean values of r^-3 obtained from relativistic self-consistent-field (SCF) wavefunctions are in good agreement with the experimental orbital and spin-dipole values of ⟨r^-3⟩, while relativistic effects can only explain about 50% of the experimental spin part. This discrepancy is mainly due to core polarization, which has been estimated by use of non-relativistic unrestricted SCF wavefunctions. The core polarization contribution has been corrected for relativistic effects using correction factors obtained from a comparison between relativistic and non-relativistic restricted SCF wavefunctions. Most of the spin part of the hyperfine interaction can be explained in this way. By use of hyperfine radial integrals obtained from relativistic SCF wavefunctions the quadrupole and octupole moments have been evaluated with the result: Q = -0.46 b. (Sternheimer uncorrected) and Ω = 0.62(8) n.m.b. respectively.

The relative intensities of the 6.13, 6.92 and 7.12 MeV gamma rays from the nuclear reaction ¹⁹F(p,αγ)¹⁶O have been measured for proton energies between 1.3 MeV and 2.2 MeV, in steps of about 6 keV. In addition, angular distributions of gamma rays have been measured on and around the different resonances for 22 proton energies in the energy interval. A lithium-drifted germanium detector with an energy resolution of about 0.5% has been used, permitting the two 7 MeV components to be fully resolved. The behaviour of the three components at the various resonances differ somewhat.

An investigation of the doubly-excited quartet levels in Be II and the displaced term system of Be I is described. Beam-foil spectra of beryllium (500-1 600 Å, 2 000-6 000 Å) showed several transitions which were assigned to doubly-excited Be II. A term scheme for these quartet levels is proposed. A number of the observed lines were also identified with the Be I 2pnl¹L, ³L system. Radiative lifetimes have been determined for several excited levels in Be I and Be II.

The absorption spectrum of CoD has been produced by using a King furnace. The spectrum in the region 3 500-7 500 Å was recorded photographically in a 10.685 metre concave grating spectrograph. Six perturbed bands belonging to the A³Φ₄-X³Φ₄ sub-system have been analysed. Computer methods have been used to calculate term values and to evaluate molecular constants, some of which are (in cm^-1).

A single crystal structure refinement of Cr₃P shows that the compound crystallizes with the Fe₃P type structure. Atomic positional parameters and interatomic distances are reported and discussed. An examination by X-ray diffraction methods shows that Zr₃P can dissolve hydrogen in solid solution. Some evidence is presented to show that the hydrogen atoms are accomodated in tetrahedral holes between the zirconium atoms.

The equilibrium charge distributions for boron ions after interacting with a carbon foil have been measured for incident particle energies between 0.25 and 1.75 MeV.

UV photoemission spectra from clean, Cs and Cs + O₂ coated Ag are reported. The results, which include temperature and angular dependence, are discussed in terms of the Ag band structure. The spectral structure due to the conduction band is discussed with reference to simple two band models with the relativistic effects accounted for in a qualitative manner. New structure is predicted in the absorption spectra of binary solid solutions of free electron like metals.