The role of condensed-phase reactions in the burning of mixtures of fusible metals with ammonium perchlorate

1984 ◽  
Vol 20 (2) ◽  
pp. 161-163
Author(s):  
G. V. Ivanov ◽  
V. G. Surkov ◽  
L. N. Karmadonov ◽  
A. M. Viktorenko
Keyword(s):  
Ammonium Perchlorate ◽  
Condensed Phase ◽  
Condensed Phase Reactions

Role of silver compounds in promoting the thermal decomposition of ammonium perchlorate

1986 ◽  
Vol 1 (3) ◽  
pp. 235-251 ◽  
Author(s):  
Andrew K. Galwey ◽  
Mohamed A. Mohamed ◽  
David S. Cromie
Keyword(s):  
Thermal Decomposition ◽  
Ammonium Perchlorate ◽  
Silver Compounds

scholarly journals Protein crystal lattices are dynamic assemblies: the role of conformational entropy in the protein condensed phase

IUCrJ ◽  
2018 ◽  
Vol 5 (2) ◽  
pp. 130-140 ◽  
Author(s):  
Margarita Dimova ◽  
Yancho D. Devedjiev
Keyword(s):  
Condensed Phase ◽  
Protein Structures ◽  
Van Der Waals Interactions ◽  
Protein Crystal ◽  
Crystal Formation ◽  
Conformational Entropy ◽  
Crystal Lattices ◽  
Crystal Contacts ◽  
First Time

Until recently, the occurrence of conformational entropy in protein crystal contacts was considered to be a very unlikely event. A study based on the most accurately refined protein structures demonstrated that side-chain conformational entropy and static disorder might be common in protein crystal lattices. The present investigation uses structures refined using ensemble refinement to show that although paradoxical, conformational entropy is likely to be the major factor in the emergence and integrity of the protein condensed phase. This study reveals that the role of shape entropy and local entropic forces expands beyond the onset of crystallization. For the first time, the complete pattern of intermolecular interactions by protein atoms in crystal lattices is presented, which shows that van der Waals interactions dominate in crystal formation.

Chemical Reactions In Condensed Phases

2006 ◽  
Author(s):  
Abraham Nitzan
Keyword(s):  
Chemical Reactions ◽  
Condensed Phase ◽  
Chemical Change ◽  
Classical Mechanics ◽  
Chemical System ◽  
Condensed Phases ◽  
Molecular Configuration ◽  
Middle Stage ◽  
Condensed Phase Reactions ◽  
Energy Surfaces

Understanding chemical reactions in condensed phases is essentially the understanding of solvent effects on chemical processes. Such effects appear in many ways. Some stem from equilibrium properties, for example, solvation energies and free energy surfaces. Others result from dynamical phenomena: solvent effect on diffusion of reactants toward each other, dynamical cage effects, solvent-induced energy accumulation and relaxation, and suppression of dynamical change in molecular configuration by solvent induced friction. In attempting to sort out these different effects it is useful to note that a chemical reaction proceeds by two principal dynamical processes that appear in three stages. In the first and last stages the reactants are brought together and products are separated from each other. In the middle stage the assembled chemical system undergoes the structural/chemical change. In a condensed phase the first and last stages involve diffusion, sometimes (e.g. when the species involved are charged) in a force field. The middle stage often involves the crossing of a potential barrier. When the barrier is high the latter process is rate-determining. In unimolecular reactions the species that undergoes the chemical change is already assembled and only the barrier crossing process is relevant. On the other hand, in bi-molecular reactions with low barrier (of order kBT or less), the rate may be dominated by the diffusion process that brings the reactants together. It is therefore meaningful to discuss these two ingredients of chemical rate processes separately. Most of the discussion in this chapter is based on a classical mechanics description of chemical reactions. Such classical pictures are relevant to many condensed phase reactions at and above room temperature and, as we shall see, can be generalized when needed to take into account the discrete nature of molecular states. In some situations quantum effects dominate and need to be treated explicitly. This is the case, for example, when tunneling is a rate determining process. Another important class is nonadiabatic reactions, where the rate determining process is hopping (curve crossing) between two electronic states. Such reactions are discussed in Chapter 16.

Role of Poly(vinyl alcohol) in the Crystal Growth of Ammonium Perchlorate

2008 ◽  
Vol 8 (3) ◽  
pp. 1060-1066 ◽  
Author(s):  
Anuj A. Vargeese ◽  
Satyawati. S. Joshi ◽  
V. N. Krishnamurthy
Keyword(s):  
Crystal Growth ◽  
Ammonium Perchlorate ◽  
Vinyl Alcohol ◽  
Poly Vinyl Alcohol
Sign in / Sign up

Export Citation Format

Share Document