Volume 28, Issue 1
January 1987, pages 1-93
pp 1- January 1987 Comments
Some subtleties regarding regularizations in computing the soliton energy of degenerate systems are discussed.
pp 1-8 January 1987 Quantum Mechanics
We consider the application of semiclassical approximation to relativistic potentials for massless particles where the kinetic energy is a nontrivial, nonlocal operator. Quantization rules are derived for an arbitrary confining potential and compared to some exact results forS-waves. These results admit of a partial generalization to smalll values.
pp 9-14 January 1987 Particle Physics
We obtain the superconformal transformation laws for theN=2,D=4 SSYM. The transformations involve Yang-Mills fields and the corresponding field strength tensor is not constrained to be self antidual. We explicitly demonstrate the closure of the superconformal algebra.
pp 15-22 January 1987 Particle Physics
It is shown that SU(2)×U(1) can be broken at the tree level, without the occurrence of global potential minima that break U(1)e.m., in supergravity models that are more general than those proposed by Nilles, Srednicki and Wyler. The study comprises an analysis of models with a general soft supersymmetry-breaking structure as well as those of the Hall-Lykken-Weinberg type.
pp 23-34 January 1987 Particle Physics
We make an analysis of the Gribov-Lipatov relation using the phenomenological forms of the structure functionF2ep. Our analysis indicate breakdown of the relation at PETRA energies. Plausible reasons of the breakdown of Gribov-Lipatov relation are discussed together with its phenomenological form.
pp 35-39 January 1987 Particle Physics
The claim of Mohapatra and Maharana thattb(s) is a better scaling variable thant(lns)2 is put to test in the case of Λ-p scattering, after parametrizingb(s) asC1 +C2(lns)α. It was observed that in this case the data also prefer anα value which is close to those obtained by Mohapatra and Maharana for other scattering processes.
pp 41-44 January 1987 Nuclear Physics
Fusion cross-sections for16O +16O reaction earlier calculated in classical microscopic equations of motion approach, with Lennard-Jones form ofNN interaction potential are overestimated compared to the experimental data at lower energies. This large deviation was attributed to possible break down of classical approximations at lower energies. The aim of this paper is to show that this discrepancy was rather due to certain assumptions made in the specification of initial conditions; in particular due to neglect of Coulomb interaction between the colliding ions at far off distances. Use of Lennard-Jones potential is also critically examined.
pp 45-50 January 1987 Molecular Physics
The theoretical hybridization model of Vega is adapted to the tetrahedral environment around the nitrogen nucleus in eleven amino acids to estimate the orbital occupation numbers using the experimental values of the quadrupole coupling constant and asymmetry parameter of14N quadrupole resonance and the results are discussed.
pp 51-58 January 1987 Molecular Physics
An algorithm recently proposed by us for the direct determination of pure state one-electron density matrices (P) under externally imposed constraints has been remodelled. The modified algorithm is applied to the construction of ground state potential energy curve of lithium hydride molecule usingknown values of dipole moments of LiH at various internuclear distances as theexternal constraint. The equilibrium internuclear distances (Rc) is seen to be unaffected by the constraint, but the force constant improves remarkably. The relevant features of the constrained density vis-a-vis those of the unconstrained one are analyzed revealing some of the improved features of the constrained density.
pp 59-71 January 1987 Spectroscopy
Transient excited singlet state absorption (ESSA) has been studied in Rhodamine 6G in ethanol using a nitrogen laser and nitrogen laser-pumped dye laser. Broad absorption with several submaxima and possible shoulders, which represent the vibrational structure, has been observed in Rhodamine 6G in the region, 4175–4640 Å. The position of the lowest vibrational level of the first excited singlet stateS1 has been determined from the crossing point of the long and short wavelength spectral wings of absorption and fluorescence respectively. The energy level scheme of the molecule has been obtained with the help of the absorption and fluorescence spectra recorded. The observed structure in ESSA has been tentatively interpreted to be due to transitions from the different vibrational levels ofS1 to one or more vibrational levels of the upper singlet electronic stateS4.
pp 73-79 January 1987 Solid State Physics
Solid solutions of CsCl-Br in five different concentrations were prepared in sealed quartz tubes by heating the mixture to 1123°K for 6–8 hr and quenching to room temperature. X-ray diffractograms were taken at eight different temperatures between room temperature and 90°K for these solid solutions using the YPC50NM powder diffractometer and a continuous flow cryostat. The observed lattice parameters for each sample at each temperature obtained from the powder diffractograms were then extrapolated to give the true lattice parameters using the least square method with Nelson-Riley extrapolation scheme. The values of the true lattice parameters at each concentration and at each temperature were tabulated and the results discussed. It is shown that the lattice parameters vs temperature for some concentrations exhibit an anomalous behaviour.
pp 81-86 January 1987 Solid State Physics
X-ray diffraction and colour centre studies have been carried out on RbCl-RbBr mixed crystals. The lattice constant closely follows the linear form of Vegard’s law. The mean Debye-Waller factor shows a highly nonlinear composition dependence. The composition dependence of the F-band peak position is slightly nonlinear but that of the F-band half-width is highly nonlinear. The Ivey-Mollow relation holds for this system with an index of 2.5. The ‘size effect’ is found to have a dominant effect on the F-band width.
pp 87-93 January 1987 Comments
We reexamine the recent claim that the soliton of the 1 + 1 dimensional field theories does not survive quantum corrections if the adjacent minima of the potential do not have same curvature and show that it is in fact possible to choose counter terms such that the quantum correction to the soliton mass is finite.
Volume 93 | Issue 6
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