Table of contents

It is shown that the generalized Hulthén potential (GHP) is a shape invariant potential with a translation of parameters. The exact energy spectrum of this potential is obtained in terms of a shape invariant approach. The supersymmetric WKB approximation gives the same result.

The ground state configurations of the solution to Skyrme's topological soliton model for systems with baryon number larger than 1 are well approximated with rational map ansatz, without individual baryon coordinates. Here the canonical quantization of the baryon number 2 system, which represents the deuteron, is carried out in the rational map approximation. The solution, which is described by the six parameters of the chiral group SU(2) × SU(2), is stabilized by the quantum corrections. The matter density of the variational quantized solution has the required exponential large distance falloff and the quantum numbers of the deuteron. Similarly to the axially symmetric semiclassical solution, the radius and quadrupole moment are, however, only about half as large as the corresponding empirical values. The quantized deuteron solution is constructed for representations of arbitrary dimension of the chiral group.

Using the functional integration method the dynamical symmetry breaking in the U(3) Nambu–Jona-Lasinio model has been studied. The possibility of spontaneous CP symmetry breaking in the model under consideration was shown. With the help of the bosonization procedure the propagators of quarks, scalar and pseudoscalar fields were evaluated in one loop approximation. The masses of the nonets of scalar and pseudoscalar mesons are calculated.

Excitation energies, oscillator strengths and transition probabilities for electric-dipole-allowed and inter-combination transitions among the 25 LS levels belonging to the (1s²2s²2p⁶)3s²3p, 3s3p², 3s²3d, 3p³, 3s3p3d, 3s²4s, 3s²4p, 3s²4d, 3s²4f and 3s3p4s configurations of Ar VI are calculated using extensive configuration-interaction (CI) wave functions. From our transition probabilities we have also calculated the radiative lifetimes of doublet and quartet states of Ar VI. Our results are compared with other available theoretical calculations and the experimental data. To assess the importance of relativistic effects on our calculated values, we have also carried out calculations in the intermediate-coupling scheme. These effects are incorporated through the Breit–Pauli approximation via spin–orbit, spin–other–orbit, spin–spin, Darwin and mass correction terms. Small adjustments to the diagonal elements of the Hamiltonian matrices have been made so that the energy splittings are as close as possible to the experimental values. The energy splitting of 54 fine-structure levels, the oscillator strengths and transition probabilities for some strong dipole-allowed and intercombination transitions and the lifetimes of some fine-structure levels are presented and compared with available experimental and other theoretical values. Our lifetime for the 3s3p(¹P^o)3d(²P^o) level calculated in intermediate-coupling scheme, while differing significantly from our LS value, shows excellent agreement with the experimental result of Pinnington et al. In this calculation we also predict new data for several levels where no other theoretical and experimental results are available.

The spectrum of Iodine was recorded in the 300–2000 Å region on a variety of normal incidence spectrographs using triggered spark and sliding spark sources. The earlier analysis of 5s²5p², 5s5p³ and 5s²5p (6s + 5d) configurations of I IV was confirmed. The 5s²5p(7s + 8s) and 5s²5p(6d + 7d) four odd parity configurations were investigated. Thirty out of thirty two levels of these configurations have been established on the basis of 76 lines in the 350–535 Å region. Hartree–Fock (HF) and least-squares-fitted (LSF) calculations were carried out to interpret the I IV spectrum satisfactorily. On the basis of the lines of many ns and nd three-member series the ionization potential of I IV was calculated to be 325,500 ± 200 cm^-1 (40.35 ± 0.02 eV) (5p²P_1/2 of I V).

The spectrum of iodine was recorded in the 300–1250 Å on 3 m and 6.65 m normal incidence spectrographs at the Antigonish laboratory and Zeeman Laboratory using a triggered spark and sliding spark sources. The earlier analysis of the 5s²5p³, 5s²5p²(5d + 6s) and 5s5p⁴ configurations has been confirmed, the level 5s²5p²5d²S_1/2 has been found and levels of four new even parity configurations viz. 5s²5p²ns (n = 7,8) and 5s²5p²nd (n = 6,7) with J ≤ 7/12, have been established. One hundred and ninety (190) new lines have been classified in I III spectrum and 69 new levels have been established. Hartree–Fock (HF) and least-squares-fitted (LSF) calculations support the interpretation presented in this report. Using 5s²5p²ns (n = 6,7,8) and 5s²5p²nd (n = 5,6,7) series Ionization Potential has been calculated as 238500 ± 200 cm^-1 (29.56 ± 0.02 eV) for I IV 5s²5p²³P₀.

X-ray reflectivity curves at 20 keV photon energy of alpha-quartz spherically curved crystals have been measured using a micrometric synchrotron beam at the ESRF BM5. Six thin quartz crystals samples with curvature radii of 150 and 250 mm have been studied. Experimental results are compared with diffraction profile calculations using a lamellar model and a good agreement is found.

It is recently discussed that a plasma system with drifting ions at near the acoustic phase speed becomes susceptible to weak but finite electron inertial delay effect. In such plasma condition, the linear normal modes of acoustic oscillations undergo resonant linear growth. Such situation exists naturally in transonic zones of boundary plasma layers. The present contribution considers this as a specific case to describe the possible role of an external source driving on the usual ion acoustic soliton solution in the unstable region of the transonic zone assumed to have finite extension. A driven Korteweg–de Vries equation is obtained that is not exactly integrable. It is shown by numerical analysis that the usual acoustic soliton solution exists only for infinitely long wavelength source perturbation. For short wavelength (but within the limit of the long wavelength approximation) source perturbations interesting solutions of single unit of localized oscillatory shock-like structure are obtained. Possible physical interpretations of the results are included in the text.

A new concept of the x-ray source based on a low-pressure microwave discharge that is confined in a magnetic mirror trap and heated at electron cyclotron resonance conditions is described. It is demonstrated that the energetic electrons accelerated on the resonance hyperboloid of one sheet surface type, form a rotating ring, which is located in the middle cross section of the trap. When the ring strikes a metal target, an x-ray radiation is produced. A 100 keV radiation is obtained by using 2.45 GHz microwaves of 150 W.

Theoretical and numerical studies are presented of the nonlinear amplitude modulation of dust–acoustic (DA) waves propagating in an unmagnetized three component, weakly-coupled, fully ionized plasma consisting of electrons, positive ions and charged dust particles, considering perturbations oblique to the carrier wave propagation direction. The stability analysis, based on a nonlinear Schrödinger-type equation (NLSE), shows that the wave may become unstable; the stability criteria depend on the angle θ between the modulation and propagation directions. Explicit expressions for the instability rate and threshold have been obtained in terms of the dispersion laws of the system. The possibility and conditions for the existence of different types of localized excitations have also been discussed.

Localized nonlinear dust kinetic Alfvén waves are investigated in a collisionless two-ion-temperature dusty plasma consisting of a negatively charged, extremely massive, cold dust fluid and ions of two different temperatures. It is found that finite amplitude density dips and humps propagating at sub-Alfvénic speed can coexist. Further, at super-Alfvénic speed, kink type solitons are also found to exist along with density humps. It has been shown that the properties of these solitary waves are significantly modified by their speed, obliqueness, the presence of second component of ions and the ratio of temperatures of the two ion species. The results of the present investigation would be useful in understanding the formation of coherent soliton structures in laboratory, space and astrophysical dusty plasma systems, such as in the planetary rings and cometary tails.

Higher order nonlinearity and dispersive effects are obtained for a multicomponent plasma consisting of cold positive and negative ions and two-temperature isothermal electrons by our pseudopotential technique. The advantage of the method developed here is that instead of solving a second order inhomogeneous differential equation at each order in the usual reductive perturbation method, we are to solve a first order inhomogeneous equation at each order except at the first. Here we have carried out calculations up to third order which is one order higher than that of the usual reductive perturbation method. Moreover we have studied a double layer of the same plasma using a new technique.

A rate calculation and new kinetics model have been applied to a short pulse, high power XeCl laser, in order that the UV preionization design for large volume glow discharge is realized. A laser beam of 450 mJ, 15 ns duration, cross section of 2 × 1.78 cm², cavity length of preionization and glow discharge 900 mm, and a beam quality element of 3.5 cm along the discharge direction and 2.1 cm along the y direction has been achieved. It shows that, the laser in the composition of gas mixtures HCl : Xe : He = 0.1% : 1% : 98.9%, 37.5 kV indicates a best pulse profile with more than 5.4% efficiency and a beam divergence angle smaller than 3 mrad. The laser acting on CMR and quartz material makes block materials eject plasma spilling eclosion without burning etching.

The phase diagram of magnetron sputter-deposited Al-Cu thin films is simpler than the equilibrium diagram. Above 86.17 at.%Cu, the films are single αCu phase. Below, the microstructure consists of a mixture of the solid solution αAl phase and an intermetallic compound phase, the previous θ(Al₂Cu) phase for the 1.8 to 45.99 at.%Cu films and an unexpected (Cu₃Al) phase for 49.07 to 66.64 at.%Cu films. We note the appearance of a phase separation (αAl + αCu + Cu₃ Al) in 66.64 at.%Cu films. The microhardness and the young modulus of the sputtered films increase regularly with Cu concentration reaching a maximum (H ≈ 8000 MPa and E ≈ 200 GPa). This phenomenon of strengthening of aluminium by means of copper is essentially due to a combination of solid solution effects and grain size refinement.

It is demonstrated that the growth of CuCl crystals in a single crystal of NaCl can be realized by the doping of the melted NaCl solution with copper. The absorption spectra in ambient exhibit peaks allotted to the excitonic transitions with a displacement towards great energies. The mean size of the crystallites is approximately 20 Å. From absorption spectra analysis, it was also shown that the heat treatments lead to an increase of the size of the CuCl particles. X-ray diffraction patterns demonstrate the good crystallinity of the matrix as well as the presence of CuCl in this matrix.