[...]... mutilated Instead of the three adjustable parameters of (21) we have now only one : the size R, The second virial coefficient B, is defined by the development of the gas equation into powers of I - V and is given theoretically by I In the development of B, into powers of - the first two terms can be T I identified with the corresponding terms of Van der Waals’ equation : 100 Years of Physical Chemistry 20... and that any influence of a third molecule upon the interaction between the first two is only a small perturbation effect of a smaller order of magnitude than the interaction itself These attractive 10 100 Years of Physical Chemistry F LONDON I5 forces can therefore simply be superposed according to the parallelogram of forces, and they are consequently able to represent the fact of a general cohesion... theory of the interaction of macroscopic bodies in terms of the bulk static and dynamic dielectric properties 1 100 Years of Physical Chemistry 2 has been presented by Lifshitz.5 Proton movements in hydrogen-bonded solids and liquids may contribute to the binding energy as well as to the dielectric constant, electrical conductivity and intense continuous infrared absorption.6 If one or both of the... Here u0 = V*(I e -is the pruper frequency of da T a2 &as - m f .) the two elastic systems, if isolated from each other (R+= a), m is their reduced mass Assumand ing or R3, we have deveIoped the square roots in (12) into powers of (a]Ra) The lowest state of this system of six oscillators will therefore be given, according to (11), by : 100 Years of Physical Chemistry 8 F LONDON h E , = - (Y,+ 2 hv -++... onset of covalent bonding, as identified by Haberland et ul The paper by Haberland et al represents one of the first attempts to use clusters as a means of mapping the development of electronic band structure The data show clear evidence of a steady progression from the van der Wads behaviour expected of a collection of closed shell atoms, through to the on-set of metallic character As part of a ‘bigger... Department of Chemistry, University of Cambridge, Lensfeld Road, Cambridge, UK CB2 1EW Commentary on: The general theory of molecular forces, F London, Truns Faraday SOC., 1937,33, 8-26 The origin of the substantial attractive forces between nonpolar molecules was a serious problem in the early 20th century While much was known of the strength of these forces from the Van der Waals equation of state... electrons to valence states in small mercury clusters The positions of the valence states P 23 24 100 Years of Physical Chemistry are considered to be sensitive to changes in the nature of the bonding between atoms in the clusters This latter experiment is not so strongly influenced by structural changes that may occur as a result of ionisation, and which may create a significant difference between... cohesion, like gravitation ; this presumption actually implied 4 100 Years o Physical Chemistry f F LONDON 9 a very suggestive and simple explanation of the parallelism observed in the different effects of these forces When, however, one began to try t o explain the molecular forces by the general conceptions of the electric structure of the molecules i t seemed hopeless to obtain such a simple result... feature of London’s paper is its emphasis on the zero-point motion of electrons: it is the intermolecular correlation of this zero-point motion that is responsible for dispersion forces London’s Section 9 extends the idea of zero-point fluctuations to the interaction of dipolar molecules If their moment of inertia is small, as it is for hydrogen halide molecules, then even near the absolute zero of temperature... Slater and J G Kirkwood, Physic Rev., c++ = 0'11 2.68 38.6 94'3 247 12 100 Yenrs of Physical Chemistry F LONDON 4 8 17 Systematics of the Long Range Forces.' The formula (15) applies quite generally for freely movable molecules so long as the interaction energy can be considered as small compared with the separation of the energy-levels of the molecules in question ; i.e so long as With this restriction, . theory of the interaction of macroscopic bodies in terms of the bulk static and dynamic dielectric properties 1 2 100 Years of Physical Chemistry. 100 Years of Physical Chemistry F. LONDON 9 a very suggestive and simple explanation of the parallelism observed in the different effects of