Muon-fluorine entangled states in molecular magnets

The information accessible from a muon-spin relaxation experiment can be limited due to a lack of knowledge of the precise muon stopping site. We demonstrate here the possibility of localizing a spin polarized muon in a known stopping state in a molecular material containing fluorine. The muon-spin precession that results from the entangled nature of the muon spin and surrounding nuclear spins is sensitive to the nature of the stopping site. We use this property to identify three classes of sites that occur in molecular magnets and describe the extent to which the muon distorts its surroundings.     

Disappearing Polymorphs Revisited

Nearly twenty years ago, Dunitz and Bernstein described a selection of intriguing cases of polymorphs that disappear. The inability to obtain a crystal form that has previously been prepared is indeed a frustrating and potentially serious problem for solid‐state scientists. This Review discusses recent occurrences and examples of disappearing polymorphs (as well as the emergence of elusive crystal forms) to demonstrate the enduring relevance of this troublesome, but always captivating, phenomenon in solid‐state research. A number of these instances have been central issues in patent litigations. This Review, therefore, also highlights the complex relationship between crystal chemistry and the law.     

Kβ X-ray emission spectroscopy offers unique chemical bonding insights: revisiting the electronic structure of ferrocene

Kβ X-ray emission spectroscopy (XES) is emerging as a powerful tool for the study of chemical bonding. Analyses of the Kβ XES of ferrocene (Fc) and ferrocenium (Fc(+)) are presented as further demonstrations of the capabilities of the technique. Assignments of the valence to core (V2C) region of these spectra as electric dipole-allowed cyclopentadienyl (Cp) → Fe 1s transitions demonstrate that XES affords electronic structural insight into the energetics of ligand-based molecular orbitals (MOs). Combined with K-edge X-ray absorption spectroscopy (XAS), we show that XES can provide analogous information to photoemission spectroscopy (PES). Density functional theory (DFT) analyses reveal that the V2C transitions in Fc/Fc(+) derive their intensity from Fe 4p admixture (on the order of 5-10%) into the Cp-based MOs from which they originate. These 4p admixtures confer bonding character to the Cp-based a(2u) and e(1u) MOs to at least the extent of backbonding contributions to frontier MOs from higher-lying Cp π* MOs.     

Theoretical fluid mechanics

Experiments and Models for Young Physicists. By A. D. Bulman. (London: John Murray, 1966.) [Pp. iv + 87.] 18s.

The Velocity of Light. By J. H. Sanders. [Pp. x + 144.]

Early Electrodynamics. The First Law of Circulation. By R. A. R. Tricker. [Pp. vii + 217.]

Kinetic Theory: Volume 1. The Nature of Gases and of Heat. By S. G. Brush. [Pp. xi + 181.]

Men of Physics: Irving Langmuir. By Albert Rosenfeld. [Pp. 369.]

Phyiics is Fun. Book Three. By Jim Jardine. (London: Heinemann Educational Books Ltd., 1966.) [Pp. vii + 168.] Hard cover, 13s. 6d.; paper cover, 11s. 6d.

Transformations in Optics. By Lawrence Metz. (Wiley &; Sons, 1965.) [Pp. viii + 116.] 70s.

Relativity and Common Sense. By Hermann Bondi. (Heinemann, 1965.) [Pp. xi + 177.] 8s. 6d.

Introduction to the Theory of Relativity and the Principles of Modern Physics. Hüseyin Yilmaz. (Blaisdell Publishing Co., 135 West 50th Street, New York, 1965.) [Pp. xiv + 216.] 68s.

Lectures on General Relativity. By A. Trautman, F. A. E. Pirani and H. Bondi. (Prentice Hall International, 28 Welbeck Street, W.1, 1965.) [Pp. 459.] 40s.

Direct Generation of Electricity. Edited by K. H. Spring. (Academic Press, 1966.) [Pp. x + 410.] 105s.

Heat Bibliography. (Published for the Ministry of Technology by H.M.S.O., 1965.) [Pp. viii + 478.] £2 7s. 6d.

Physics of Quantum Electronics. By P. L. Kelley, B. Lax and P. E. Tannenwald. (McGraw Hill, Maidenhead, Berks., 1966.) [Pp. xxvii + 861.] £9 12s. Od.

Nuclear Forces. By D. M. Brink. (Pergamon, 1966.) [Pp. viii + 232.] 17s. 6d.

Physics of the Solar Corona. (2nd Edition.) By I. S. Shklovskii. (Pergamon Press, 1966.) [x + 475.] £6.

Interstellar Gas Dynamics. (2nd revised edition.) By S. A. Kaplan. (Pergamon Press, 1966.) [Pp. xii + 126.] 40s.

Quantum Mechanics. By A. S. Davydov. (Pergamon Press, 1966.) [Pp. xiii + 680.] 90s.

Radioactivity and its Measurement. By Wilfred B. Mann and S. B. Garfinkel. (Van Nostrand, 1966.) [Pp. 160.] 18s.

Nonequilibrium Thermodynamics in Physics. By A. Katchalsky and Peter F. Curran. (O.U.P., 1966.) (Source of book, Harvard University Press.) [Pp. x + 248.] 68s.

Magnetic Domains and Techniques for their Observation. By R. Carey and E. D. Isaac. (English Universities Press, 1966.) [Pp. viii + 168.] 50s.

The Quantum Equation and the Theory of Fields. By H. T. Flint. (Methuen, 1966.) [Pp. xii + 146.] 36s.

Diffraction. Coherence in Optics. By M. Françon. (Pergamon, 1966.) [Pp. ix + 139.] 20s.

Variation Principles. By B. L. Moiseiwitsch. (Wiley, 1966.) [Pp. x + 310.] 90s.

O Level Examples in Physics. By C. W. Kearsey and E. L. Clark. (Longmans Green &; Co. Ltd., 1966.) [Pp. vi + 232.] 8s.

Junction Transistors. By J. J. Sparkes. (Pergamon Press, 1966.) [Pp. viii + 249.] 25s.

Concise Applied Thermodynamics. By J. Phillips and J. B. Owen-Jones. (D. Van Nostrand Co. Ltd., 1966.) [Pp. xii + 302.] Students' edition (paper), 21s.; Library (cloth), 45s.

The Physics Teachers Handbook. By L. A. Redman. (Spectrum Books Ltd., 1966.) [Pp. 232.] 15s.

Dictionary of Semiconductor Physics and Electronics. English/German, German/English. Editor, Werner Bindmann. (Pergamon Press, 1966.) [Pp. 615.] £8.

Space Science. Edited by W. N. Hess. (Blackie, 1966.) [Pp. xv + 919.] 120s.

Physics Education. (The Institute of Physics and the Physical Society.)     

Water vapor sorption in starch granules

A mathematical model proposed for diffusion in spherical particles can be solved on a digital computer. The model includes particle size distribution and variable diffusion coefficient of the form D = Doe^αC, where D is the diffusion coefficient, D₀ and α are constants, and C is the moisture content. Isothermal experimental measurements were made gravimetrically on a Cahn electrobalance by vacuum sorption techniques. The model adequately predicts the absorption characteristics of water vapor in starch granules. Although swelling is neglected in the model, it does contribute to sorption characteristics.     

Laser-driven fast electron collimation in targets with resistivity boundary

We demonstrate experimentally that the relativistic electron flow in a dense plasma can be efficiently confined and guided in targets exhibiting a high-resistivity-core-low-resistivity-cladding structure analogous to optical waveguides. The relativistic electron beam is shown to be confined to an area of the order of the core diameter (50 μm), which has the potential to substantially enhance the coupling efficiency of electrons to the compressed fusion fuel in the Fast Ignitor fusion in full-scale fusion experiments.     

The local determination of Jordan bases for H-self-adjoint operators

Let H be an invertible self-adjoint operator on a finite dimensional Hilbert space $\text{X}$. A linear operator A is said to be H-self-adjoint (or self-adjoint relative to H) if HA = A¹H. Let σ(A) denote, as usual, the spectrum of A. If A is H-self-adjoint, then A is similar to A¹ and λ ∈ σ(A) implies λ̄ ∈ σ (A), so that the spectrum of A issymmetric with respect to the real axis. Given spectral information for A at an eigenvalue λ₀ (≠ λ̄₀), we investigate the corresponding information at λ̄₀ and, in particular, the unique pairing of Jordan bases for the root subspaces at λ₀ and λ̄₀.