Effect of molecular constitution and conformation on positron binding and annihilation in alkanes

In this paper the experimental results concerning the crystalline properties of the unsaturated aliphatic hydrocarbons, the simpler oxygen- and sulphur-compounds of carbon, the halogen-compounds, and the simpler aromatic hydrocarbons are given. Ethylene . —Ethylene, prepared from alcohol and sulphuric acid, was purified by liquefying it and distilling it twice. It crystallises very well, large prisms being formed. Two distinct cleavage systems occur, one parallel to a prism and the other parallel to the basal plane (or an orthodome). The doublerefraction is of middle strength; the extinction is in some sections parallel to the prismatic cleavage, in others it is not. The angle of the optical axes is large, and the optical character negative. These optical observations show that ethylene crystallises in the monoclinic crystal system.

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XIV. Researches into the molecular constitution of the organic bases

Philosophical Transactions of the Royal Society of London ◽

10.1098/rstl.1851.0017 ◽

1851 ◽

Vol 141 ◽

pp. 357-398 ◽

Cited By ~ 6

Keyword(s):

Physical Properties ◽

Royal Society ◽

General Outline ◽

Organic Bases ◽

History Of ◽

The Subject ◽

Molecular Constitution

About twelve months ago I had the honour of presenting to the Royal Society an account of a series of researches into the molecular constitution of the volatile organic bases: at present I beg to submit to the consideration of the Society the history of a new group of alkaloids, which, although intimately connected with the former by their origin, differ from them altogether by their properties, and especially in not being volatile . The members of this new group of alkaloids are so numerous, their deportment is so singular, and their derivatives ramify in so many directions, that I have not as yet been able to complete the study of these substances in all their bearings; nor is it my intention to go fully into the chemistry of the subject in the present communication, my object being merely to establish the existence of these bodies, and to give a general outline of their connection with the volatile bases, and of their most prominent chemical and physical properties, reserving a detailed description of their salts and derivatives to a future memoir.

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I.—Lord Kelvin: A Centenary Tribute

Proceedings of the Royal Society of Edinburgh ◽

10.1017/s0370164600024858 ◽

1926 ◽

Vol 45 (1) ◽

pp. 1-2

Author(s):

J. Alfred Ewing

Keyword(s):

Royal Society ◽

World Wide ◽

Vortex Motion ◽

Dynamical Theory ◽

Dissipation Of Energy ◽

The Earth ◽

Molecular Constitution ◽

Lord Kelvin

In this the centenary year of Lord Kelvin's birth it is fitting that the Society should call to remembrance one who was for long its most distinguished Fellow, who first became its President at the age of thirty-nine, and was repeatedly re-elected to the office, which he held for twenty-one years in all, and who used the Society as a medium for the publication of many of his most brilliant discoveries. In the long list of his published papers there are at least one hundred and twenty items communicated to the Royal Society of Edinburgh. No other contributor has done so much to give to our Proceedings and Transactions a world-wide and lasting fame. It was to this Society that he brought, in 1849, his account of Carnot's Theory, which marks the beginning of his study of Thermodynamics, and it was in our Transactions that he published his epochmaking series of papers on the “Dynamical Theory of Heat” from 1851 to 1854. It was here in 1852 that he propounded the doctrine of the Dissipation of Energy. It was here that his investigations of underground temperature and the secular cooling of the Earth appeared in 1860 and 1862. It was here in 1865 that he “briefly refuted” the doctrine of Uniformity in Geology. Here, too, were published his long series of papers on Vortex Motion and Vortex Atoms, from 1867 to 1881, and much of his work on the molecular constitution of matter. Here he first showed, in germ, his mariner's compass, in 1874.

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Molecular Dynamics of a Crystal

Proceedings of the Royal Society of Edinburgh ◽

10.1017/s0370164600007835 ◽

1904 ◽

Vol 24 ◽

pp. 205-224

Author(s):

Lord Kelvin

Keyword(s):

Molecular Dynamics ◽

Single Atom ◽

Single Atoms ◽

Mathematical Investigation ◽

Molecular Constitution

§ 1. The object of this communication is to partially realise the hope expressed at the end of my paper of July 1 and July 15, 1889, on the “Molecular Constitution of Matter”:—“The mathematical investigation must be deferred for a future communication, when I hope to give it with some further developments.” The italics are of present date.Following the ideas and principles suggested in §§ 14–20 of that paper (referred to henceforth for brevity as M. C. M.), let us first find the work required to separate all the atoms of a homogeneous assemblage of a great number n of molecules to infinite distances from one another. Each molecule may be a single atom, or it may be a group of i atoms (similar to one another or dissimilar, as the case may be) which makes the whole assemblage a group of i assemblages, each of n single atoms.

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XIV. On the molecular constitution of crystals

The London Edinburgh and Dublin Philosophical Magazine and Journal of Science ◽

10.1080/14786445508641940 ◽

1855 ◽

Vol 10 (64) ◽

pp. 108-115

Author(s):

Robert T. Forster

Keyword(s):

Molecular Constitution

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VIII. The influence of Molecular constitution and temperature on magnetic susceptibility. Part IV. - Further applications of the molecular field

Philosophical Transactions of the Royal Society of London. Series A, Containing Papers of a Mathematical or Physical Character ◽

10.1098/rsta.1920.0008 ◽

1920 ◽

Vol 220 (571-581) ◽

pp. 247-289 ◽

Cited By ~ 3

Keyword(s):

Magnetic Susceptibility ◽

Experimental Evidence ◽

Royal Society ◽

Molecular Theory ◽

Molecular Field ◽

Molecular Configuration ◽

Material Medium ◽

The Subject ◽

Molecular Constitution ◽

Crystalline Symmetry

The present work is a continuation of that published in ‘Phil. Trans., Royal Society,’ vol. 214, pp. 109-146, 1914 (Parts I. and II.) and vol. 215, pp. 79-103, 1915 (Part III.). It will lead to clearness in the following development of the subject if a brief résumé of these papers is given. A t the same time, I wish to discuss one or two points in connexion with the views which have been previously advanced and the relation between mechanical and molecular theory. In Part I. the experimental evidence brought forward has justified the hypothesis of molecular distortion enunciated at the outset. We have thereby been led to regard the molecular configuration of a material medium as a distorted one, and this applies particularly to a substance which is crystalline. The extent of this distortion is small, but is sufficient to account for the observed change of specific susceptibility which occurs on crystallization. Such change will naturally depend upon the particular crystalline symmetry assumed by the substance.

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