DEPENDENCE OF MOLECULAR PROPERTIES OF CONJUGATED COMPOUNDS ON THE STATE OF ELECTRONIC EXCITATION

1953 ◽  
Vol 31 (4) ◽  
pp. 439-447 ◽  
Author(s):  
C. Sándorfy

Reasons are given for the belief that many new chemical reactions may be obtained in the excited electronic states of the molecules. By the examples of nitrobenzene, trans → cis isomerization of stilbene and azobenzene, by an interpretation of experimental results concerning acidity and basicity of certain bodies in the excited states, and the evaluation of the charges and dipole moments of the C==N group in different excited states, it is shown how the chemical and physicochemical properties of the molecule may vary from one state to another.

1973 ◽  
Vol 6 (4) ◽  
pp. 485-501 ◽  
Author(s):  
G. Cilento

It is well known that excited states may be generated chemically in biological systems as evidencex and by the phenomenon of bioluminescence and it is natural to suspect that they may also be generated and used in dark processes (Szent-Györgyi, 1941; Steele, 1963; Cilento, 1965; White & Wei, 1970; Whiteet al.1971). Förster (1967) has pointed out that electronic excitation and subsequent transfer processes may occur in biological dark systems despite the fact that the energy available from enzymic processes is too low to excite aromatic amino acids and other biochemical structures. Hastings (1968) suggests that in some organisms light emission is just an alternative to the formation of an active species.


Author(s):  
Tian Lu ◽  
Qinxue Chen ◽  
Zeyu Liu

Although cyclo[18]carbon has been theoretically and experimentally investigated since long time ago, only very recently it was prepared and directly observed by means of STM/AFM in condensed phase (Kaiser et al., <i>Science</i>, <b>365</b>, 1299 (2019)). The unique ring structure and dual 18-center π delocalization feature bring a variety of unusual characteristics and properties to the cyclo[18]carbon, which are quite worth to be explored. In this work, we present an extremely comprehensive and detailed investigation on almost all aspects of the cyclo[18]carbon, including (1) Geometric characteristics (2) Bonding nature (3) Electron delocalization and aromaticity (4) Intermolecular interaction (5) Reactivity (6) Electronic excitation and UV/Vis spectrum (7) Molecular vibration and IR/Raman spectrum (8) Molecular dynamics (9) Response to external field (10) Electron ionization, affinity and accompanied process (11) Various molecular properties. We believe that our full characterization of the cyclo[18]carbon will greatly deepen researchers' understanding of this system, and thereby help them to utilize it in practice and design its various valuable derivatives.


Author(s):  
Tian Lu ◽  
Qinxue Chen ◽  
Zeyu Liu

Although cyclo[18]carbon has been theoretically and experimentally investigated since long time ago, only very recently it was prepared and directly observed by means of STM/AFM in condensed phase (Kaiser et al., <i>Science</i>, <b>365</b>, 1299 (2019)). The unique ring structure and dual 18-center π delocalization feature bring a variety of unusual characteristics and properties to the cyclo[18]carbon, which are quite worth to be explored. In this work, we present an extremely comprehensive and detailed investigation on almost all aspects of the cyclo[18]carbon, including (1) Geometric characteristics (2) Bonding nature (3) Electron delocalization and aromaticity (4) Intermolecular interaction (5) Reactivity (6) Electronic excitation and UV/Vis spectrum (7) Molecular vibration and IR/Raman spectrum (8) Molecular dynamics (9) Response to external field (10) Electron ionization, affinity and accompanied process (11) Various molecular properties. We believe that our full characterization of the cyclo[18]carbon will greatly deepen researchers' understanding of this system, and thereby help them to utilize it in practice and design its various valuable derivatives.


Open Physics ◽  
2008 ◽  
Vol 6 (4) ◽  
Author(s):  
Alexander Rusakov ◽  
André Zaitsevskii

AbstractExcited electronic states of the Au3 cluster are studied within the shape-consistent small-core relativistic pseudopotential model using many-body multipartitioning perturbation theory. Vertical transition energies and dipole moments are evaluated. For highly symmetric isomer, these theoretical results are in reasonable agreement with spectroscopic data from experiments.


2020 ◽  
Vol 224 ◽  
pp. 448-466 ◽  
Author(s):  
Gianluca Levi ◽  
Aleksei V. Ivanov ◽  
Hannes Jónsson

A direct optimization method for obtaining excited electronic states using density functionals is presented.


2004 ◽  
Vol 224 (2) ◽  
pp. 157-163 ◽  
Author(s):  
Annie Hansson ◽  
Anders Pettersson ◽  
Peder Royen ◽  
Ulf Sassenberg

Approximate self-consistent orbitals for excited electronic states of cis - and trans -1, 3- butadiene are obtained by a modification of Roothaan’s procedure, in the non-empirical π-electron approximation. The integrals used were evaluated by Parr & Mulliken for calculation of the ground-state electronic wave function. The effects of configuration interaction are calculated by an approximate method and compared with an exact calculation. Molecular orbitals have been obtained both with and without the auxiliary condition that spatial factors of both α and β spin-orbitals should be members of a single orthogonal set. Semiempirical values for the basic integrals, due to Pariser & Parr, have also been used to calculate the energies of excited states by the approximate configuration interaction method. Energy levels derived from the Pariser-Parr integrals are in close agreement with observed levels, which differ considerably from those calculated from the Parr-Mulliken non-empirical integrals.


1974 ◽  
Vol 61 (8) ◽  
pp. 3039-3042 ◽  
Author(s):  
Barbara J. Garrison ◽  
Henry F. Schaefer ◽  
William A. Lester

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