Volume 4, Issue 6
June 1975, pages 247-289
pp 247-263 June 1975 Quantum Mechanics
A non-perturbative theory is proposed in this article in which an energy independent effective Hamiltonian is obtained for open-shell systems. We have given a diagrammatic version of theory to facilitate the analysis of the problem. The theory has been applied to a model 4-π electron problem, for calculating the lowestπ-π* singlet and triplet energy levels of transbutadiene. Comparison with full Cl calculation indicates the excellent workability of the theory.
pp 264-270 June 1975 Nuclear And Particle Physics
We discuss the condition for the presence of isoscalar parity violating neutral currents and notice that it is present in most gauge-theoretic models of weak interactions. We investigate the possibility of testing its presence in e+e− colliding beams and find that parity violation in the reaction e+e−→Λ°Λ° would provide an unambiguous test for such a current.
pp 271-275 June 1975 Solids
Absorption of polarization in fluorocarbon foil electrets has been studied under different conditions. The mode of surface charge decay of thermo-and radio-electrets has been explained by the mechanism of polarization trapping in electrets.
pp 276-289 June 1975 Spectroscopy
The extensive thermal emission spectrum attributed to the diatomic bromides of calcium, strontium and barium has been observed in the visible region at temperatures about 2200–2400° C, using a vacuum graphite furnace. Many new bands,viz., 141 in CaBr, 53 in SrBr and 68 in BaBr, have been recorded and classified. The vibrational constants agree with those determined by earlier workers and involved the ground state in each case. The transition C→X apears in each molecule and consists of two equally intense systems,viz., C1→X and C2→X. The general spectroscopic features of the C→X systems of the bromides of the II A sub group of the periodic table have been compared. They exhibit a close structural similarity and furnish a good example of homologous spectra. The system C→X in all these molecules arises from a C2π−X2Σ+ transition where the2π state appears to be intermediate between Hund’s cases (a) and (b).
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