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This ability to transform the excitation energy of photon into heat can be a crucial property for photoprotection by molecules such as melanin. [2] Fast internal conversion reduces the excited state lifetime, and thereby prevents bimolecular reactions. Bimolecular electron transfer always produces a reactive chemical species, free radicals.
In chemistry, homoconjugation has two unrelated meanings: In acid–base chemistry, homoconjugation is an alternate name for the phenomenon of homoassociation . In organic chemistry, homoconjugation is a type of conjugated system where two π-systems are separated by one non-conjugating group.
Crystalline solids and molecular solids are two opposite extreme cases of materials that exhibit substantially different transport mechanisms. While in atomic solids transport is intra-molecular, also known as band transport, in molecular solids the transport is inter-molecular, also known as hopping transport.
Excited state intramolecular proton transfer (ESIPT) is a process in which photoexcited molecules relax their energy through tautomerization by transfer of protons.Some kinds of molecules could have different minimum-energy tautomers in different electronic states, and if the molecular structure of minimum-energy tautomer in the excited state is proton-transferred geometry between neighboring ...
Intramolecular reactions, especially ones leading to the formation of 5- and 6-membered rings, are rapid compared to an analogous intermolecular process. This is largely a consequence of the reduced entropic cost for reaching the transition state of ring formation and the absence of significant strain associated with formation of rings of these ...
In heterogeneous electron transfer, an electron moves between a chemical species present in solution and the surface of a solid such as a semi-conducting material or an electrode. Theories addressing heterogeneous electron transfer have applications in electrochemistry and the design of solar cells.
In Marcus theory the energy belonging to the transfer of a unit charge (Δe = 1) is called the (outer sphere) reorganization energy λ o, i.e. the energy of a state where the polarization would correspond to the transfer of a unit amount of charge, but the real charge distribution is that before the transfer. [9]
Intramolecular forces such as disulfide bonds give proteins and DNA their structure. Proteins derive their structure from the intramolecular forces that shape them and hold them together. The main source of structure in these molecules is the interaction between the amino acid residues that form the foundation of proteins. [ 7 ]