Theoretical chemistry fundamental forces

Barthelot,Marcellin(1827-1907). A French scientist who is considered as the founder of modern thermochemistry. He developed the theory of detonation and most of the early theoretical knowledge pertaining to expls, as well as contributing to many branches of chemistry other than expls. The author of the fundamental work on expls "Sur la Force des Matieres Explosives d apres la Thermochimie , which even today is of great value although written nearly 100 years ago... 

It is true that all molecular and atomic forces ultimately find their root in the mutual behavior of the constituent parts of the atoms, viz., the nuclei and the electrons. They may theoretically all be derived from the fundamental wave equations. It is, however, convenient, as in other branches of physics and chemistry, to treat the various forms of mutual interaction of atoms as different forces, acting independently. We shall therefore follow the usual procedure and treat such forces as the nonpolar van der Waals (dispersion) forces, the forces of the electrostatic polarization of atoms or molecules by ions or by dipoles, the mutual attraction or repulsion Coulomb forces of ions and of dipoles, the exchange forces leading to covalent bonds, the repulsion forces due to interpenetration of electronic clouds, together with the Pauli principle, etc., all as different, independently acting forces. 

In the course of time, however, a rather sophisticated scheme has developed of quantitative treatments of solute-solvent interactions in the framework of LSERs. The individual parameters employed were imagined to correspond to a particular solute-solvent interaction mechanism. Unfortunately, as it turned out, the various empirical polarity scales feature just different blends of fundamental intermolecular forces. As a consequence, we note at the door to the twenty-first century, alas with melancholy, that the era of combining empirical solvent parameters in multiparameter equations, in a scientific context, is beginning to fade away. As a matter of fact, solution chemistry researeh is increasingly being occupied by theoretical physics in terms of molecular dynamics (MD) and Monte Carlo (MC) simulations, the integral equation approach, etc. 

The choice of fundamental approximation, combined with the choice of parameter values, defines a particular SEMOT method, analogous to a force field in MM. Several established and novel SEMOT methods have been reviewed and compared elsewhere [54]. Among the three popular SEMOT methods mentioned earlier, MNDO/d is least widely available in commercial software packages. The other two methods, AMI and PM3, differ only in their parameterization. Since the PM3 method was parameterized more recently and more carefully, it is expected to be more reliable and will be the focus of discussion here. However, performance varies, so it should be compared with that of the experiment for related systems before putting faith in the predictions. Note that AMI and PM3 predictions are included in the Computational Chemistry Comparison and Benchmark Database (CCCBDB), which is a convenient, on-line resource for comparing theoretical predictions with experimental data [55]. 

This review concentrates on the fundamentals of supermolecule model chemistries for clusters of atoms/molecules held together by weak chemical forces. The principles behind the appropriate selection of theoretical method and basis set for a particular class of weak noncovalent interactions provide the foundation for understanding more complex computational schemes that might require the user to specify more than just a method and/or basis set, such as highly efficient fragmentation schemes [e.g., the effective fragment potential (EFP) method, " the fragment molecular orbital (FMO) method, the... 

Many phenomena of interest in science and technology take place at the interface between a liquid and a second phase. Corrosion, the operation of solar cells, and the water splitting reaction are examples of chemical processes that take place at the liquid/solid interface. Electron transfer, ion transfer, and proton transfer reactions at the interface between two immiscible liquids are important for understanding processes such as ion extraction, " phase transfer catalysis, drug delivery, and ion channel dynamics in membrane biophysics. The study of reactions at the water liquid/vapor interface is of crucial importance in atmospheric chemistry. Understanding the behavior of solute molecules adsorbed at these interfaces and their reactivity is also of fundamental theoretical interest. The surface region is an inhomogeneous environment where the asymmetry in the intermolecular forces may produce unique behavior. 

No aspect of chemistry is more fundamental to the science than is the study of the nature of the chemical bond. Solids exhibit the complete range of bonding behavior and offer opportunity, therefore, for gaining special insight into the nature of interatomic binding forces. The regularity of many solids facilitates experimental and theoretical examination of chemical bonds and allows the interpretation of the properties of solids in fundamental atomic terms. This volume is concerned with these aspects of solid-state chemistry. Thus it furnishes a fundamental basis for later volumes. 

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