Table of contents

A detailed analysis is given of the properties of symmetry transformation generators for singular Lagrangian systems. It is shown that they are very similar in their phase space structure, especially in their dependence on primary first class constraints, to the Hamiltonian. The manner in which gauge transformation generators are built up out of primary and secondary first class constraints is explicitly elucidated. The behaviour of the invariance group of the theory with respect to adoption of Dirac brackets and gauge constraints is clarified.

A version of the model formulated earlier by the authors is considered. It admits a direct interpretation of the multiple production of hadrons in the central collisions of relativistic nuclei on the basis of the two-component quark-glue structure of nucleons.

In this paper the model of multiple particle production in hadron collisions at the energies from 10 GeV to 10 TeV, suggested by the authors earlier is further developed. The discussion is based on the quark-gluon hadron picture.

The Dirac technique for treatment of singular Lagrangian systems is extended to cover cases where the constraints may be explicitly time dependent. Necessary and sufficient conditions for recovery of the Hamiltonian form for the equations of motion are found. The case of time dependent gauge constraints is also discussed.

Lifetime measurements using the beam-foil technique have been made for 10 levels in Mg I and for 11 levels in Mg II. Lifetimes have been calculated for the same levels using the numerical Coulomb-approximation (NCA) method, and the results are compared with the experimental data. Whereas good agreement exists between theory and experiment for Mg II levels and for some of the low lying Mg I levels, there are large disagreements for some higher lying levels in Mg I. Results from NCA calculations on ionized elements in the Mg I sequence are compared with experimental data. In some but not every case the NCA results agree with experimental data, as for Mg I.

Electronic transitions between Rydberg levels and the ground state in the SeH molecule have been observed in absorption after flash photolysis in the wavelength region 1600 to 1330 Å. Rotational constants have been determined for these Rydberg states as well as for the ²Π_i ground state. The corresponding transitions for the SeD molecule have also been observed and analysed. The ionisation potential for SeH is estimated to be 9.06 ± 0.01 eV (73 070 ± 100 cm^-1).

The beam-foil method has been used to measure lifetimes for six levels in Si I. The results are compared with emission data and theoretical values. Improved experimental values are also given for a number of previously measured levels in Si II-Si IV.

It is known that nonuniform field oscillating in time with a high frequency tends on average to remove a particle towards region with small field intensity. In case of irregular h.f. field, with finite correlation time τ, this effect is shaded due to stochastic instabilities and diffusion. In this paper we obtain rather simple master equation describing drift and diffusion of a test particle. The main property of the equation is nonmonotonous, with change of sign, dependence from Ωτ where Ω is the characteristic frequency of the field oscillations, of the drift and diffusion coefficients. Some consequencies are discussed. An important result is that in case of standing wave h.f. fields with finite τ the particle localization does not take place even in the presence of rather significant damping forces.

A method for producing both on- and off-axis paraboloidal mirrors of high optical quality, is described. The mirror surface is formed when a liquid polymer in a vessel on a horizontal table rotating at a constant angular velocity, cures, leaving a surface-finished paraboloid ready for coating. Interferograms of both on- and off-axis paraboloidal mirrors made this way, are shown. Mirrors of surface quality λ/5 peak-to-peak for λ = 633 nm, have been made. It is expected that the method can be used for the production of both large and medium size paraboloidal mirrors to considerably lower costs than by the present methods.

A general dispersion relation is derived for a plasma in a helical magnetic field of arbitrarily large amplitude. Comparisons are made with previous results for large amplitude waves emitted by pulsars as well as for the free electron laser. Discrepancies between the present new coupling coefficients and those of previous authors are pointed out and explained.

The electric quadrupole interaction at ¹¹¹Cd and ¹⁸¹Ta impurity nuclei in a terbium host lattice has been measured as a function of temperature and pressure by time differential perturbed angular correlations. Both the observed temperature dependence: (d ln q/dT)_300K = - 5.7(3) × 10^-4 K^-1 (Cd) and (d ln q/dT)_300K = - 7.2(4) × 10^-4 K^-1 (Ta), and the observed pressure dependence: (d ln q/dP)_300K = + 12.6(1.8) × 10^-3 kbar^-1 (Cd) and (d ln q/dP)_300K = + 6.9(2.2) × 10^-3 kbar^-1 (Ta), disagree with point charge lattice sum predictions.