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Relative band intensities of the comet tail system (A²Π-X²Σ) of CO⁺ and of the α(A²Π-X²Σ) and β(B²Σ-X²Σ) systems of BO have been measured photoelectrically. They have been interpreted with the aid of Franck-Condon factors q_{ν'νdouble prime} and r-centroids r_{ν'νdouble prime} to show the variation of electronic transition moment R_e(r) with internuclear separation r and thereby to give `smoothed' arrays of relative vibrational transition probabilities p_{ν'νdouble prime} and intensities at infinite temperature I_infinity. The isotope effect on the Franck-Condon factors and intensities in the case of ¹⁰BO and ¹¹BO band systems has been examined.

This paper is concerned with the validity of Green's linearized integral equation, or the ring approximation of the virial expansion, in the theory of liquids. It is shown that this approximation is applicable only at high temperatures and low densities, and, by comparing the solution of Green's linearized equation with the exact solution by Gursey for the one-dimensional square-well potential; that the singularities in Green's equation are attributed to the linear approximation and have nothing to do with the phase transition. The situations are the same in the approximation of Kirkwood (linearized form), of Abe, of Morita, and of Meeron.

The energy spectra of protons emitted into a small solid angle in the forward direction from separated isotopes ¹⁹F, ²⁷Al, ⁵⁴Fe, ⁵⁶Fe, ⁵⁹Co, ⁵⁸Ni, ⁶⁰Ni, ⁶³Cu, ⁶⁵Cu and ⁶⁴Zn bombarded with 14.1 MeV neutrons are measured with a scintillation counter telescope. The spectra obtained are compared with those measured by Storey et al. in 1960, who, using 14.1 MeV neutrons, observed the spectra of protons emitted at 90° into a large solid angle. Peaks due to direct interactions are prominent at the higher proton energies, but little evidence is found for systematic structure similar to that observed in the inelastic scattering of protons of energy 11 to 23 MeV. It is suggested that lower energy peaks found in the present spectra, and in those of other workers, corresponding to excitations of the residual nucleus of 7 MeV are not due to protons, but are in fact deuterons mostly from the ground state n, d pick-up reaction. The `nuclear temperatures' found from the lower energy protons of the present experiment are in good agreement with those measured by Storey et al.

Neutral deuterium atoms of energy 8 MeV from the Birmingham cyclotron were passed through hydrogen and deuterium gas at low pressure. Ionized particles were separated by the cyclotron magnetic field from the original beam and the numbers in each beam were found by counting tracks on a nuclear emulsion.

Cross sections for ionizing collisions were found to be 1.6 ± 0.25 × 10^-18 cm² and 2.3 ± 0.25 × 10^-18 cm² in hydrogen and in deuterium respectively.

Time-of-flight techniques have been applied to the measurement of γ-ray spectra from the interaction of 14 MeV neutrons with various nuclei. The results for carbon, water, magnesium, aluminium, nickel, copper and lead are presented and are compared with the results from other experiments using lower energy neutrons. Assignments are made for the reaction processes in the light nuclei and isotopic assignments are made for the medium- and heavy-weight nuclei

The left-right stripping asymmetry of the ground state, and the first excited state proton groups, has been measured at several angles of emission, when a ⁹Be target was bombarded with 6 MeV deuterons which had been polarized by elastically scattering them from carbon. Measurements have also been made at two angles of the ⁴⁰Ca (dp) ⁴¹Ca ground state group asymmetry.

The results confirm that polarization effects in stripping are caused predominantly by the central part of the deuteron and proton distoring potentials. The opposite sign of the ⁹Be (dp) ¹⁰Be ground state and first excited state asymmetries enables an unambiguous mixing ratio for the J_n values possible in stripping to the first excited state, to be assigned.

The azimuthal dependence of the cross section at the second of two deuteron elastic scatterings from carbon has been determined at an energy of about 6 MeV. It was found that the left-right part of the asymmetry was small and probably negative, which implies that the vector polarization either changes sign between the two scatterings, or that the tensor polarizations are large. There was no evidence for polarizations of the <T₂₂> type.

Following a theoretical discussion of Néel spike formation by the extension and subsequent collapse of a domain tube which joins an inclusion to a domain wall, a quantitative study has been made of the phenomena. The results are discussed in terms of a formula given by Brenner, and an attempt is made to assess the importance of the phenomena in the explanation of coercivity.

Before advancing any theory concerning the `squareness' or switching characteristics of a `square loop' ferrite it is necessary to assume a model for the domain (or rotational) configuration. In an attempt to obtain a knowledge of this configuration experimentally, observations were made of Bitter patterns on polycrystalline magnesium-manganese ferrite. A technique was developed which enabled the progress of a magnetization reversal to be followed in a single grain of the material.

As a result of these observations it was postulated that the magnetization in each grain of the polycrystalline material lay along a [111] direction, and that the magnetization reversed by the motion of 180° domain walls. Hysteresis loops and pulse shapes calculated on the basis of this model showed a close resemblance to the experimental curves.

The velocity and absorption of infinitesimal plane sound waves have been measured in neon-helium, argon-helium and krypton-helium mixtures, with molar fractions of helium from 0 to 1 in each mixture The measurements were made at 25 c, at a frequency of 700 kc/s, and at pressures from 0 1 to 2 atm The observed velocity of sound was correlated with values calculated from simple mixture thermodynamics, the measured absorption coefficients agreed with those calculated from a formula derived by Kohler

The propagation of small amplitude compression waves through a plasma in a static magnetic field is discussed In contrast to the usual treatment of this type of problem we shall not treat the ions as a fixed neutralizing back-ground but shall include them in the dynamics of the problem The problem is discussed in the general case in which the thermal velocity distribution is not negligible The method of solution is to use the linearized Boltzmann equation in conjunction with Maxwell's equations to obtain a distribution function and dispersion relation To obtain the dispersion relation an approximation method is used and it is shown that over the greater part of the frequency range the oscillations are of a characteristic wave number We show that the inclusion of the ions in the dynamics is justified by the fact that at integral multiples of the ion gyrotrequency the ions play the dominant role. The results obtained show that the waves are undamped The graph of the distribution function for particles with large velocities shows a fine structure which indicates that at these velocities collisions become important, especially for particles moving perpendicular to the field and direction of propagation

An experimental technique is described for accelerating tritium and ³He ions in a 1 MeV h.t. set and recovering the gas used by the ion source. Energy levels in ⁶He at 1.71 and 3.4 MeV and in ⁶Li at 2.19, 3.56, 4.3, 5.35, 5.6, 6.63, 7.4, 837 and 9 3 MeV were observed in a study of the reactions ⁷Li(t, α)⁶He and ⁷Li (³He, α)⁶ Li at bombarding energies in the range 600 to 900 kev. A classification of the levels has been attempted assuming charge independence of nuclear forces and good agreement is obtained with the intermediate coupling model suggested by Inglis in 1953 for a coupling parameter near the (LS) extreme.