Molecular energetics

The reactions taking place at the growing surface of plasma-deposited a-C H were reviewed by Jacob [29], and from this discussion emerged a framework to understand the a-C H film deposition mechanism. This framework is to some extent equivalent to the subplantation model, since it emphasizes the role of energetic molecular ions. In addition, it takes into account the role of neutral radicals. 

Molecular Energetics. Molecular energies can be computed in a variety of ways including empirical fixed valence potentials, full force field potentials, and semi-empirical molecular orbital techniques (CNDO-2, INDO, MINDO-3, MNDO, PCILO). 

Intermolecular Energetics. Molecular calculations have long been criticized as unrealistic in considering only isolated molecules. Many examples now appear in the literature with molecular mechanics computations on two or more molecules (5). These types of calculations are very time consuming and difficult to analyze. Still, some excellent progress has been made on two or more interacting molecules using techniques such as those available in CHEMLAB. 

This nitramine is claimed to be the most energetic molecular explosive known to man (which the editor doubts). 

B. Klecker, E. Moebius, D. Hovestadt, M. Scholer, and G. Gloeckler. Discovery of Energetic Molecular Ions (NO+ and 02+) in the Storm Time Ring Current, Geophys. Res. Lett., 13(1986) 632-635. 

After a substantial range of examples of EIMS mass spectra of peptides had accumulated, it became clear that difficulties and ambiguities of interpretation could be expected (Anderegg et al., 1976). Applications of EIMS methods declined, as softer ionisation methods - such as fast-atom bombardment (FAB) MS - became established (Biemann and Martin, 1987 Biemann, 1989). These methods create less-energetic molecular ions and the ensuing fragmentation is therefore less extensive (this usually ensures the presence of an intense molecular ion peak in the spectrum) and spectra are therefore more easily interpreted. 

Simulations of band-gap properties of imperfect energetic molecular solids, such as the cyclotrimethylene trinitramine (RDX) And pentaetythritol tetranitrate (PETN) crystals with vacancies and dislocations, have been attempted recently by Kuklja and Kunz. [27-31] Their results have indicated that compression of the RDX crystal in the presence of single [28-30] and dimmer... 

For reasons already explained in the foregoing, the study of the deformation of cellulose gels is entwined with much greater theoretical difficulties. In order to minimize the latter as far as possible, two conditions should be fulfilled. Firstly attention should be focussed on swollen objects, thus diminishing the complications due to energetic molecular interaction, and secondly isotropic objects should be available as a starting material. 

Temperature also affects the rate of chemical reactions. An increase in temperature generally results in an increased rate of reaction. This can be understood by noting that most reactions, viewed from the molecular perspective, require some energy input to get them started. Increasing the temperature creates more energetic molecular collisions, and the rate increases. Experimental studies of reaction rates as a function of temperature provide the data needed to measure the activation energy. 

The measurement of the time dependence of gium may be used to probe various chiral aspects of excited state energetics, molecular dynamics, and reaction kinetics. Although there are some time-dependent circular polarization effects due to molecular reorientations that parallel time-dependent linear polarization measurements, the most interesting studies are those that involve the time-dependence of intrinsic molecular chirality. For a sample containing one chiral luminescent lanthanide chromophore, it might be the case that there are processes that affect chirality occurring on the same time scale as emission that could be probed by time-dependent CPL. To date, however, there have been no reports of such studies, and all of the time-dependent CPL measurements have involved racemic mixtures. 

We have seen that when two pure liquids mix to form an ideal liqiud mixture at the same T and p, the total volume and internal energy do not change. A simple molecular model of a binary liquid mixture will elucidate the energetic molecular properties that are consistent with this macroscopic behavior. The model assumes the excess molar entropy, but not necessarily the excess molar internal energy, is zero. The model is of the type sometimes called the qmsicrystalline lattice model, and the mixture it describes is sometimes called a simple mixture. Of course, a molecular model like this is outside the realm of classical thermodynamics. 

ABSTRACT. In these two review lectures, we combine Quantum Chemistry, Crystalline structure analyses and Molecular-Dynamics simulations to obtain an insist into the Physics and Chemistry of shock induced detonation wave propagation mechanisms in energetic molecular crystals in order to help define a microscqnc theory of detonations. 

These two lectures are devoted to a microscopic view of the phenomena involved in a shock induced detonation process in an energetic molecular crystal. 

Gillan, E.G. Synthesis of nitrogen-rich carbon nitride networks from an energetic molecular azide precursor. Chem. Mater. 12, 3906-3912 (2000)... 

Specific molecular features. Compounds with unusually high proportions of nitrogen, N-N bonds, 0-0 bonds, and others, are generally quite reactive and some are unstable. Some compounds possessing such energetic molecular structures are listed in Table 12.10. 

---