Bulk properties of matter

The molecular potential energy surface is one of the most important concepts of physical chemistry. It is at the foundations of spectroscopy, of chemical kinetics and of the study of the bulk properties of matter. It is a concept on which both qualitative and quantitative interpretations of molecular properties can be based. So firmly is it placed in the theoretical interpretation of chemistry that there is a tendency to raise it above the level of a concept by ascribing it some physical reality. 

Boltzmann molecular beam experiments, and from the bulk properties of matter. 

As has long been known, every derivation of the bulk properties of matter from its atomic properties by statistical methods encounters essential difficulties of principle. Their effect is that in all but the simplest cases (i.e., equilibrium) the development does not take the form of a deductive science. This contrasts with the usual situation in physics e.g., Newtonian or relativistic mechanics, electromagnetism, quantum theory, etc. The present paper, after focusing on this difficulty, seeks a way out by exploring the properties of a special class of statistical kinetics to be called relaxed motion and to be defined by methods of generalized information theory. 

Kinetic theory A theory which accounts for the bulk properties of matter in terms of the constituent particles. 

While the internal vibrational modes of molecules can display sharp spectral features, the vibrational spectra of modes of bulk matter are broad and relatively featureless. Nonetheless, Raman and infrared methods can be used to study the bulk, the intermolecular degrees of freedom of condensed matter systems. A great deal of information on bulk degrees of freedom has been extracted from electronic spectroscopy, particularly at low temperatures. Such experiments, however, rely on the influence of the medium on an electronic transition. Using ultrafast Raman techniques, including multidimensional methods, and emerging far-IR methods, it is possible to examine the bulk properties of matter directly. 

Living organisms can be considered as physicochemical systems interacting with their surroundings. Thermodynamics is the science of the energetics of such systems. It is a macroscopic theory, being concerned with the bulk properties of matter the link between the thermodynamics and molecular processes is provided by the theory of statistical mechanics. 

In contfast to intermolecular forces, intramolecular forces hold atoms together in a molecule. (Chemical bonding, discussed in Chapters 9 and 10, involves intramolecular forces.) Intramolecular forces stabilize individual molecules, whereas intermolecular forces are primarily responsible for the bulk properties of matter (for example, melting point and boiling point). 

Even if not directly observable, intermolecular forces influence the microscopic and bulk properties of matter, being responsible for a variety of interesting phenomena such as the equilibrium and transport properties of real fluids, the structure and properties of liquids and molecular crystals, the structure and binding of Van der Waals (VdW) molecules (which can be observed under high resolution rotational spectroscopy [5-8] or molecular beam electric resonance spectroscopy [9]), the shape of reaction paths and the structure of transition states determining chemical reactions [10]. 

Although directly observable quantum mechanical effects, such as interference and diffraction, cannot be measured for everyday macroscopic objects, these objects are made up of the nuclei and electrons of atoms, and since quantum mechanical properties control the interactions between these small units, they also control the bulk properties of matter. The stractures of bulk matter itself, and all interactions between matter and radiation, arise from the quantum mechanical behaviour of the smaller units from which it is composed. 

From the microscopic perspective on individual molecules and molecule-molecule interactions, the path toward bulk properties of matter may seem obvious just add more molecules. From Chapter 10, we know how to estimate any relevant potential energy functions for the interactions, and with this we can write the Flamiltonian for the system and integrate the Schrodinger equation to find the wavefunctions and energies. 

The text begins with an investigation of thermodynamics, the study of the transformations of energy, and the relations between the bulk properties of matter. Thermodynamics is summarized by a number of laws that allow us to account for the natural direction of physical and chemical change. Its principal relevance to biology is its application to the study of the deployment of energy by organisms. 

The simplest state of matter is a gas. We can understand many of the bulk properties of a gas—its pressure, for instance—in terms of the kinetic model introduced in Chapter 4, in which the molecules do not interact with one another except during collisions. We have also seen that this model can be improved and used to explain the properties of real gases, by taking into account the fact that molecules do in fact attract and repel one another. But what is the origin of these attractive and... 

The three representations that are referred to in this study are (1) macroscopic representations that describe the bulk observable properties of matter, for example, heat energy, pH and colour changes, and the formation of gases and precipitates, (2) submicroscopic (or molecular) representations that provide explanations at the particulate level in which matter is described as being composed of atoms, molecules and ions, and (3) symbolic (or iconic) representations that involve the use of chemical symbols, formulas and equations, as well as molecular structure drawings, models and computer simulations that symbolise matter (Andersson, 1986 Boo, 1998 Johnstone, 1991, 1993 Nakhleh Krajcik, 1994 Treagust Chittleborough, 2001). 

The student conceptions that were displayed could be categorised into three main types, namely (1) confusion between macroscopic and submicroscopic representations, (2) extrapolation of bulk macroscopic properties of matter to the submicroscopic level and (3) corrfusion over the multi-faceted significance of chemical symbols, chemical formulas as well as chemical and ionic equations. Student conceptions held by at least 10% of the students who were involved in the alternative instractional programme were identified. Several examples of student conceptions involving the use of the triplet relationship are discussed in the next section. 

The minimum size to which a sample can be reduced without qualitatively changing its properties corresponds to the correlation length. If the correlation length is small the properties of the system can be calculated by a variety of methods, for instance Hartree-Fock. The assumption is that the properties of matter in the bulk can be related to the properties of a small cluster of atoms, noting that even a cluster of three has too many degrees of freedom to be solved without considerable simplification. 

The above observation suggests an intriguing relationship between a bulk property of infinite nuclear matter and a surface property of finite systems. Here we want to point out that this correlation can be understood naturally in terms of the Landau-Migdal approach. To this end we consider a simple mean-field model (see, e.g., ref.[16]) with the Hamiltonian consisting of the single-particle mean field part Hq and the residual particle-hole interaction Hph-... 

We first review briefly the description of the bulk properties of uniform quark matter, deconfined from the /3-stable hadronic matter mentioned in the previous section, by using the MIT bag model [31]. The thermodynamic potential of f = u,d,s quarks can be expressed as a sum of the kinetic term and the one-gluon-exchange term [32, 33] proportional to the QCD fine structure... 

To summarize, in the present scenario pure hadronic stars having a central pressure larger than the static transition pressure for the formation of the Q -phase are metastable to the decay (conversion) to a more compact stellar configuration in which deconfined quark matter is present (i. e., HyS or SS). These metastable HS have a mean-life time which is related to the nucleation time to form the first critical-size drop of deconfined matter in their interior (the actual mean-life time of the HS will depend on the mass accretion or on the spin-down rate which modifies the nucleation time via an explicit time dependence of the stellar central pressure). We define as critical mass Mcr of the metastable HS, the value of the gravitational mass for which the nucleation time is equal to one year Mcr = Miis t = lyr). Pure hadronic stars with Mh > Mcr are very unlikely to be observed. Mcr plays the role of an effective maximum mass for the hadronic branch of compact stars. While the Oppenheimer-Volkov maximum mass Mhs,max (Oppenheimer Volkov 1939) is determined by the overall stiffness of the EOS for hadronic matter, the value of Mcr will depend in addition on the bulk properties of the EOS for quark matter and on the properties at the interface between the confined and deconfined phases of matter (e.g., the surface tension a). 

In contrast to molecular theory, classic thermodynamics deals only with measurable properties of matter in bulk (for example, pressure, temperature, volume, cell potential,... 

The most striking characteristic of the dissolved humic substances is their chromophoric nature. As part of the DOM, they impart a yellow-brown cast to marine and freshwaters and, hence, are part of the CDOM pool. Terrestrial hiunic substances compose a significant fraction of the riverine DOM entering the ocean. In seawater, humic substances compose 5 to 15% of the HMW DOM. Differences exist in the bulk properties of marine and terrestrial humic substances. These are summarized in Table 23.6. They have been used to trace the fate of terrestrial organic matter in the ocean. 

The essential differences between the properties of matter when in bulk and in the colloidal state were first described by Thomas Graham. The study of colloid chemistry involves a consideration of the form and behaviour of a new phase, the interfacial phase, possessiug unique properties. In many systems reactions both physical and chemical are observed which may be attributed to both bulk and interfacial phases. Thus for a proper understanding of colloidal behaviour a knowledge of the properties of surfaces and reactions at interfaces is evidently desirable. 

The science of materials may have begun in the blacksmith s forge, but the materials of tomorrow will be formulated by understanding how the properties of matter are determined by the arrangements of its atoms and molecules. Scientists understand and invent new materials by considering the properties and interactions of individual particles and predicting how those properties translate into bulk properties. This chapter continues the important task of relating atomic and molecular properties to the structure and properties of bulk matter. 

Thermodynamics deals with relations among bulk (macroscopic) properties of matter. Bulk matter, however, is comprised of atoms and molecules and, therefore, its properties must result from the nature and behavior of these microscopic particles. An explanation of a bulk property based on molecular behavior is a theory for the behavior. Today, we know that the behavior of atoms and molecules is described by quantum mechanics. However, theories for gas properties predate the development of quantum mechanics. An early model of gases found to be very successftd in explaining their equation of state at low pressures was the kinetic model of noninteracting particles, attributed to Bernoulli. In this model, the pressure exerted by n moles of gas confined to a container of volume V at temperature T is explained as due to the incessant collisions of the gas molecules with the walls of the container. Only the translational motion of gas particles contributes to the pressure, and for translational motion Newtonian mechanics is an excellent approximation to quantum mechanics. We will see that ideal gas behavior results when interactions between gas molecules are completely neglected. 

The properties that emerge in chemical studies include the exclusion principle, molecular structure and the second law of thermodynamics. Without these principles, not revealed by the laws of physics, there is no understanding of the properties of matter in the bulk. By way of example, the phenomena of optical activity and superconduction have never been fully explained by the laws of physics. 

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