Analysis and merit of the constrained-component variation in dirac theory

It is shown that the constrained-component variation generally suggested by Rosicky and Mark is very fundamental, has consistent variational features and reproduces, as a special case, earlier variational results for atomic systems obtained by Drake and Goldman. Numerical merits and demerits of this method are qualitatively assessed.     

A residual method of finite differencing for the elliptic transport problem and its application to cavity flow

A residual method of finite differencing the governing differential equation for the elliptic transport problem is presented. The new finite differencing technique is applied to (1) the one-dimensional transport problem and (2) the cavity flow problem for numerical illustrations. The results indicate the validity of the residual method of finite differencing. The usual method of term-by-term finite differencing, and considerations such as central differencing, hybrid differencing and upwind differencing are not needed in the present residual method.     

Elastic and inelastic scattering of 11.8 MEV polarized deuterons from 34S

The elastic and inelastic scattering of 11.8 MeV vector polarized deuterons from ³⁴S has been studied. Angular distributions of the cross section σ(θ) and vector analyzing power iT₁₁(θ) have been measured for the ground state and the first three excited states in ³⁴S. Optical model parameters were first obtained by fitting the elastic deuteron scattering data alone. DWBA calculations with a collective model form factor were performed for the inelastic scattering to the excited states. Coupled-channels calculations were also done both for the one-phonon and the two-phonon excited states. The optical model parameters were suitably modified to obtain simultaneous fit to elastic and inelastic data when channel coupling was introduced. The values of the vibrational parameter β₂ for one- and two-phonon states are discussed and compared with those obtained from γ-decay width studies.     

Neutral current effects in the parity violating nuclear force

The measurements of the ΔI = 1 part of the parity violating nuclear force when combined with information on neutral current couplings from neutrino scattering and pion production experiments allow an estimate of the isoscalar admixture in the neutral current if it has a vector axial-vector structure has been shown.     

Ground water recharge in Western Uttar Pradesh

The downward movement of water in the soil due to 1971 monsoon precipitation and supplemental surface irrigation has been traced at about forty-five sites in Western Uttar Pradesh, using a thin layer of moisture tagged with tritiated water. The tritiated layer was found to move down to different depths at different sites. The movement, averaged over the forty sites is found to be 96 cm, indicating that the average recharge for the year 1971 (a year of normal monsoon) was 21.5 cm of water.     

Ab initio quantum chemical investigation of intramolecular magnetic interaction in some diradical derivatives of imino nitroxide and nitronyl nitroxide

The magnetic properties of the monoradicals 2-(4-phenyl acetylene)-4,4,5,5-tetramethyl-4,5-dihydro-1H-imidozolyl-oxyl (1) and 2-(4-phenyl acetylene)-4,4,5,5-tetramethyl-4,5-dihydro-1H-imidazole-1-oxyl-3-oxide (2) and the diradicals 2,2'-(1,2-ethynediyldi-4,1-phenylene)bis[4,4,5,5-tetramethyl-4,5-dihydro-1H-imidozolyl-oxyl] (3), 2,2'-(1,2-ethynediyldi-4,1 3,1-phenylene)bis[4,4,5,5-tetramethyl-4,5-dihydro-1H-imidozolyl-oxyl] (4), and 2,2'-(1,2-ethynediyldi-4,1 3,1-phenylene)bis[4,4,5,5-tetramethyl-4,5-dihydro-1H-imidazole-1-oxyl-3-oxide] (5) are investigated by ab initio quantum chemical methods. The rule of spin alternation in the unrestricted Hartree-Fock (UHF) method clearly shows that the radical sites are antiferromagnetically coupled in 3 and ferromagnetically coupled in 4 and 5, which is consistent with a previous experiment. The molecular geometries are optimized at Hartree-Fock levels. This is followed by single-point calculations using the density functional (UB3LYP) treatment and the multiconfigurational complete active space self-consistent field (CASSCF) methodology. Magnetic exchange coupling constants are determined from the broken-symmetry approach. The calculated J values, -3.60 cm(-1) for 3, 0.16 cm(-1) for 4, and 0.67 cm(-1) for 5, are in excellent agreement with the observed values. Because of the very large size of the diradicals 3-5, the CASSCF (10,10) calculations cannot yield realistic J values. Nevertheless, the CASSCF calculations support the antiferromagnetic nature of the magnetic coupling in 3 and the ferromagnetic nature of the coupling in 4 and 5. The existence of an intramolecular magnetic coupling in 3-5 is also confirmed through computations of the isotropic hyperfine coupling constants for monoradicals 1 and 2 as well as diradicals 3-5.     

Large deflection of a semi-circular plate on elastic foundation under a uniform load

Large deflection of a simply supported semi-circular plate placed on elastic foundation and subjected to a uniform load has been investigated following Berger’s approximate method. Expressions for the deflections and bending moments are obtained and the theoretical results have been presented in the form of graphs.     

Cathodoluminescence in deformed MgO crystals

The corrected cathodoluminescence (CL) emission spectrum for undeformed MgO in the wavelength range 300–650nm consists of two overlapping bands with peaks at 425 nm (2.92 eV) and 488 nm (2.54 eV). After deformation one broad band at 466 nm (2.66 eV) of much higher intensity is observed. In the near IR part of the spectrum a further broad band occurs, consisting of a number of unresolved peaks the strongest of which is at 726 nm (1.71 eV). This band is unaffected by deformation and is thought to be due to iron impurities. Panchromatic and monochromatic SEM micrographs show that the enhanced 466 nm band luminescence comes from the slipped planes of the crystal. Shape analysis of the 466 nm emission band showed that it is a Gaussian form around the intensity maximum with an exponential high energy tail.