Geometry of Black Hole Thermodynamics

The Hessian of the entropy function can be thought of as a metric tensor on the state space. In the context of thermodynamical fluctuation theory Ruppeiner has argued that the Riemannian geometry of this metric gives insight into the underlying statistical mechanical system; the claim is supported by numerous examples. We study this geometry for some families of black holes. It is flat for the BTZ and Reissner–Nordström black holes, while curvature singularities occur for the Reissner–Nordström–anti–de Sitter and Kerr black holes.     

Anti-de Sitter quotients,bubbles of nothing,and black holes

In 3+1 dimensions there are anti-de Sitter quotients which are black holes with toroidal event horizons. By analytic continuation of the Schwarzschild-anti-de Sitter solution (and appropriate identifications) one finds two one parameter families of spacetimes that contain these quotient black holes. One of these families consists of B-metrics (“bubbles of nothing”), the other of black hole spacetimes. All of them have vanishing conserved charges. I. Bengtsson was supported by VR.     

Description of nuclear moments and nuclear spectra in the particle-rotor model

The particle-rotor model using strong coupling basis functions is briefly reviewed. Recent developments are discussed. For example, a formalism for odd-odd nuclei (and negative parity states in even nuclei) is presented. With a standard neutron-proton interaction, measured spins and moments of transitional and deformed Ho nuclei are used to extract their main configurations. Total energy calculations in the (ε, ψ)-plane based on the particle-rotor model are presented for¹⁸⁵Au.     

Evaluation of the accuracy of gran plots by means of computer calculations: Application to the potentiometric titration of the total alkalinity and carbonate content in sea water

The use of computer calculations for the determination of the systematic errors associated with Gran plots is demonstrated. The results of such calculations are used to derive “modified” Gran plots capable of locating the equivalence point both more accurately and more precisely. The general principles are exemplified by application to the determination of the total alkalinity and carbonate content in sea water by means of potentiometric titration.     

Hamiltonian treatment of self-dual antisymmetric tensors

Self-dual antisymmetric tensors occur in certain (4n + 2)-dimensional supergravity models, in particular the one connected to type IIB superstrings. So far they have been quantized only using light front methods. Here we show that the existing covariant action for such fields leads to a consistent hamiltonian system also for ordinary “timelike” dynamics, although rather complicated second class constraints are present.     

Shell structure in nuclei

A review of shell structure for spherical and a variety of deformed nuclei is presented. The microscopic-macroscopic method of Strutinsky is used to calculate potential energy surfaces with the pure harmonic oscillator and the modified harmonic oscillator. New sets of “magic numbers” for a variety of different prolate, oblate and axially asymmetric shapes are generated. Experimental evidence for the special stability caused by these shell effects is presented with special emphasis on the lightest and heaviest nuclei where the effects are most pronounced. The radial diffuseness parameter is treated as a Strutinsky variable and its significance in extrapolating into the superheavy region considered. The calculation of shell effects for high spin states is also reviewed.     

Competition between hydrogen and oxygen dissociation on palladium surfaces at atmospheric pressures

A large change in the surface and interface potential of Pd-films on SiO₂ is observed at a constant ratio between hydrogen and oxygen pressure in the ambient. This observation, which is most probably due to a competition between hydrogen and oxygen for the same dissociative adsorption sites, is described in this communication. Furthermore the potential measurements indicate the presence of another type of hydrogen adsorption sites on the oxygen covered surface.     

Argon ion laser-induced BaS BΣ-AΣ, A′Π, aΠ, and XΣ fluorescence spectra: Analysis of A A′, A a, and A′ a perturbations

The 333.6-, 351.1-, and 363.8-nm lines of a cw argon ion laser are found to coincide with the BaS B¹Σ⁺-X¹Σ⁺ (12, 0) R(17), (6, 0) P(35), and (3, 0) R(125) transitions, respectively. Fluorescence transitions from the laser-prepared upper levels terminating in X¹Σ⁺ V = 0–28, A¹Σ⁺ V = 1–3, A′¹Π V = 1–13, and a³Π₁ V = 3–12 are assigned. These results are combined with a previous analysis of the extensively perturbed BaS A¹Σ⁺-X¹Σ⁺ system [R. F. Barrow, W. G. Burton, and P. A. Jones, Trans. Farad. Soc.67, 902–906 (1971)]. Every observed perturbation of the BaS A¹Σ⁺ state is electronically and vibrationally assigned. The levels a³Π₀ V = 10–13, a³Π₁ V = 12–14, a³Π₂ V = 15, and A′¹Π V = 10–13 are sampled via their perturbations of A¹Σ⁺ V = 0–2. Although the mutual interactions of the a³Π, A′¹Π, and A¹Σ⁺ states approach Hund's case (c) limit, a complete deperturbation is performed from a case (a) starting point. Of the five lowest energy electronic states of BaS, only b³Σ⁺ remains uncharacterized. Principal deperturbed molecular constants are (in cm⁻¹, 1σ uncertainties in parentheses):

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