scholarly journals Free paths and transport phenomena in gases and the quantum theory of collisions. II.—The determination of the laws of force between atoms and molecules

1934 ◽  
Vol 144 (851) ◽  
pp. 188-205 ◽  
Keyword(s):  
Quantum Theory ◽  
Perturbation Method ◽  
Transport Phenomena ◽  
Van Der Waals ◽  
Van Der Waals Forces ◽  
Range Interaction ◽  
First Approximation ◽  
Diffusion Phenomena ◽  
The Law

The quantum theory has provided a means of calculating the interaction energies of two atoms by a perturbation method. It appears that, the short range interaction forces are due mainly to electron exchange phenomena between the two atoms, while the van der Waals forces arise from mutual polarization effects. The theory gives the first of these forces in the first approximation, while the van der Waals forces appear only in the second approximation, At large distances, where the interaction is small, it is somewhat surprising that the first approximation is not sufficient, and one is led to doubt the accuracy of the method when applied at distances at which the first and second approximations give comparable results. At these distances the mutual potential energy is comparable with the mean kinetic energy of a gas atom at ordinary temperatures, and it is therefore clear that a study of gas-kinetic collision phenomena should provide a satisfactory test of the validity of the perturbation method in this region. It is the object of this paper to carry out a number of calculations with this aim in view. In a previous paper the quantum theory of collisions was applied to gas-kinetic collisions, and it was shown that, although the classical theory can be used with accuracy to determine the law of force from viscosity and diffusion phenomena associated with heavy gases, it cannot he applied with safety to hydrogen and helium. The method to he used in such cases was given, and it was also shown that the existence of a definite total collision area—a feature of the quantum theory of scattering by a centre of force, the potential of which falls of more rapidly than r -2 at large distances—provides a further means of determining the law of force. As this collision area can now be directly measured with accuracy by molecular ray experiments, the range of applicability of tins method is considerably greater than that of methods based on transport phenomena.

II.—The Van der Waals Force between a Proton and a Hydrogen Atom

1941 ◽  
Vol 61 (1) ◽  
pp. 20-25 ◽  
Author(s):  
C. A. Coulson
Keyword(s):  
Hydrogen Atom ◽  
Power Series ◽  
Interaction Energy ◽  
Van Der Waals ◽  
Ground States ◽  
Van Der Waals Forces ◽  
Van Der Waals Force ◽  
Hydrogen Atoms ◽  
Nuclear Separation

The calculation of Van der Waals forces has acquired considerable interest recently through the work of Buckingham, Knipp and others (Buckingham, 1937; Knipp, 1939). In these papers the interaction energy between two atoms is expressed as a power series in i/R, where R is the nuclear separation, and the various terms in this series are known as dipole-dipole, dipole-quadrupole, quadrupole-quadrupole, etc… interactions. In most cases only approximate values are obtainable for the coefficients in this series, though for two hydrogen atoms in their ground states, Pauling and Beach (1935) have determined the magnitudes correct to about I in 106. In this paper we discuss the simplest possible problem of this nature, i.e. the force between a bare proton and a normal unexcited hydrogen atom. We shall show that a rigorous determination of the coefficients in the power series can be made.

Determination of van der Waals Forces

Nature ◽  
1936 ◽  
Vol 138 (3480) ◽  
pp. 77-77 ◽  
Author(s):  
H. S. W. MASSEY ◽  
R. A. BUCKINGHAM
Keyword(s):  
Van Der Waals ◽  
Van Der Waals Forces

Contact Angles for Thin Lipid Films and the Determination of London-van der Waals Forces

Nature ◽  
1968 ◽  
Vol 217 (5130) ◽  
pp. 739-740 ◽  
Author(s):  
D. A. HAYDON ◽  
J. L. TAYLOR
Keyword(s):  
Van Der Waals ◽  
Van Der Waals Forces ◽  
Contact Angles ◽  
Lipid Films

Pembagian Harta Waris dalam Tradisi Masyarakat Muslim di Gorontalo

2019 ◽  
Vol 13 (2) ◽  
pp. 187-202
Author(s):  
Hamid Pongoliu
Keyword(s):  
Islamic Law ◽  
Sharia Law ◽  
The Will ◽  
The Law

Gorontalo has a customary principle derived from sharia law, and the sharia law is sourced from the Qur'an, hadith, ijmak and qiyas (adati-hula'a to syara'a, syara'a hula'a to Kitabi), which should reflect the existence of the implementation of the distribution of inheritance in Islam in the Gorontalo community. This customary principle can be a source of law if it is a rational act, not immorality, done always repeatedly, does not bring harm and does not conflict with the law of sharak. But in reality there is the implementation of inheritance that violates Islamic law, namely the distribution by way of deliberation, the determination of the amount of heirs equally, the delay in the distribution of inheritance, wills with houses given to girls, wills not to distribute inheritance, distribution of assets it depends on the will of the heir and the delay in the distribution of inheritance on the grounds that one of the parents is still alive. The distribution by deliberation and determination of the amount of the portion for each heir are equally acceptable as long as they follow the guidelines of the Compilation of Islamic Law article 183 and the concept of takharruj which was previously preceded by the Shari'a division. After the heirs know the size of the portion, then they may agree to share it in their own way or leave the inheritance according to Shari'a and agree to give to each other with other heirs.

The Dudley Lee Case: A new approach to factual causation and its implications for transformative jurisprudence

2017 ◽  
Vol 30 (1) ◽  
pp. 273-289
Author(s):  
Anmari Meerkotter
Keyword(s):  
Case Note ◽  
Constitutional Court ◽  
Recent Contribution ◽  
New Approach ◽  
State Accountability ◽  
The Law ◽  
Transformative Impact ◽  
Constitutional Jurisprudence ◽  
Law Of Delict

The Constitutional Court (CC) judgment of Lee v Minister of Correction Services 2013 2SA 144 (CC) is a recent contribution to transformative constitutional jurisprudence in the field of the law of delict. This matter turned on the issue of factual causation in the context of wrongful and negligent systemic omissions by the state. In this case note, I explore the law relating to this element of delictual liability with specific regard to the traditional test for factual causation – the conditio sine qua non (‘but-for’) test. In particular, I note the problems occasioned by formalistic adherence to this test in the context of systemic state omissions as evidenced by the SCA judgment in the same matter. I also consider the manner in which English courts have addressed this problem. Thereafter, I analyse the CC’s broader approach to the determination of factual causation as one based on common sense and justice. I argue that this approach endorses a break from a formalistic application of the test and constitutes a step towards an approach which resonates with the foundational constitutional values of freedom, dignity and equality. Furthermore, it presents an appropriate solution to the problems associated with factual causation where systemic omissions are concerned. I then consider the transformative impact of the Lee judgment. In particular, I argue that the broader enquiry favoured by the CC facilitates the realisation of constitutionally guaranteed state accountability, and amounts to an extension of the existing norm of accountability jurisprudence. Hence, I contend that the judgment presents a further effort by the Constitutional Court to effect wholesale the constitutionalisation of the law of delict, as well as a vindicatory tool to be used by litigants who have been adversely affected by systemic state omissions.

Self-Assembly of a Chiral Cubic Three-Connected Net from the High Symmetry Molecules C60 and SnI4

2020 ◽  
Author(s):  
Daniel B. Straus ◽  
Robert J. Cava
Keyword(s):  
Organic Synthesis ◽  
Self Assembly ◽  
Van Der Waals ◽  
Van Der Waals Forces ◽  
High Symmetry ◽  
Molecular Chirality ◽  
Chiral Materials ◽  
Self Assembled ◽  
Chiral Centers

The design of new chiral materials usually requires stereoselective organic synthesis to create molecules with chiral centers. Less commonly, achiral molecules can self-assemble into chiral materials, despite the absence of intrinsic molecular chirality. Here, we demonstrate the assembly of high-symmetry molecules into a chiral van der Waals structure by synthesizing crystals of C<sub>60</sub>(SnI<sub>4</sub>)<sub>2</sub> from icosahedral buckminsterfullerene (C<sub>60</sub>) and tetrahedral SnI4 molecules through spontaneous self-assembly. The SnI<sub>4</sub> tetrahedra template the Sn atoms into a chiral cubic three-connected net of the SrSi<sub>2</sub> type that is held together by van der Waals forces. Our results represent the remarkable emergence of a self-assembled chiral material from two of the most highly symmetric molecules, demonstrating that almost any molecular, nanocrystalline, or engineered precursor can be considered when designing chiral assemblies.

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