Topological excitations

Certainly, the role of photochemical excitation may be displayed in different ways19 and even in those cases when no aromatic system is formed, topologically... 

Figure 10.1. The membrane topology proposed for D. vulgaris Hildenborough DcrH based on hydrophathy analysis and sequence homologies to other bacterial chemoreceptors (Deckers and Voordouw 1996). Shaded boxes, putative membrane-spanning (residues 9-30 and 422 31), excitation (residues 653-692), and methylation (residues 757-764) regions. The C-terminal box (residues 824-959) indicates the Hr-like region. Reprinted with permission from Xiong et al. (2000), copyright 2000 American Chemical Society.

The basic theories of physics - classical mechanics and electromagnetism, relativity theory, quantum mechanics, statistical mechanics, quantum electrodynamics - support the theoretical apparatus which is used in molecular sciences. Quantum mechanics plays a particular role in theoretical chemistry, providing the basis for the valence theories which allow to interpret the structure of molecules and for the spectroscopic models employed in the determination of structural information from spectral patterns. Indeed, Quantum Chemistry often appears synonymous with Theoretical Chemistry it will, therefore, constitute a major part of this book series. However, the scope of the series will also include other areas of theoretical chemistry, such as mathematical chemistry (which involves the use of algebra and topology in the analysis of molecular structures and reactions) molecular mechanics, molecular dynamics and chemical thermodynamics, which play an important role in rationalizing the geometric and electronic structures of molecular assemblies and polymers, clusters and crystals surface, interface, solvent and solid-state effects excited-state dynamics, reactive collisions, and chemical reactions. 

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