scholarly journals Electronic Excited States and UV–Vis Absorption Spectra of the Dihydropyrene/Cyclophanediene Photochromic Couple: a Theoretical Investigation

2020 ◽  
Vol 124 (8) ◽  
pp. 1567-1579 ◽  
Author(s):  
Rudraditya Sarkar ◽  
Marie-Catherine Heitz ◽  
Guy Royal ◽  
Martial Boggio-Pasqua
Keyword(s):  
Absorption Spectra ◽  
Excited States ◽  
Theoretical Investigation ◽  
Electronic Excited States

Electronic excited states of chromium and vanadium bisarene complexes revisited: interpretation of the absorption spectra on the basis of TD DFT calculations

2014 ◽  
Vol 43 (47) ◽  
pp. 17703-17711 ◽  
Author(s):  
Sergey Ketkov ◽  
Nikolai Isachenkov ◽  
Elena Rychagova ◽  
Wen-Bih Tzeng
Keyword(s):  
Dft Calculations ◽  
Absorption Spectra ◽  
Excited States ◽  
Time Dependent ◽  
Electronic Excited States ◽  
Td Dft ◽  
Rydberg Transitions

The influence of the (η6-arene)2M (M = Cr, V, Cr+) composition on parameters of intravalency and Rydberg transitions is explained on the basis of time-dependent DFT.

scholarly journals The Effect of N-Heterocyclic Carbene Units on the Absorption Spectra of Fe(II) Complexes: A Challenge for Theory

2020 ◽  
Author(s):  
Olga S. Bokareva ◽  
Omar Baig ◽  
Mohamed Al-Marri ◽  
Oliver Kühn ◽  
Leticia Gonzalez
Keyword(s):  
Charge Transfer ◽  
Absorption Spectra ◽  
Excited States ◽  
Partial Charge Transfer ◽  
Polypyridyl Ligands ◽  
Electronic Excited States ◽  
Heteroleptic Complexes ◽  
Ligand Charge Transfer ◽  
Exact Exchange ◽  
Triplet Excited States

<div>The absorption spectra of five Fe(II) homoleptic and heteroleptic complexes containing strong sigma-donating N-heterocyclic carbene (NHC) and polypyridyl ligands have been theoretically characterized using a tuned range-separation functional.</div><div>From a benchmark comparison of the obtained results against other functionals and a multiconfigurational reference, it is concluded that none of the methods is completely satisfactory to describe the absorption spectra.</div><div>Using a compromised choice of 20\% exact exchange, the electronic excited states underlying the absorption spectra are analyzed.</div><div>The low-lying energy band of all the compounds shows predominant metal-to-ligand charge transfer (MLCT) character while the triplet excited states have metal-centered (MC) nature, which becomes more pronounced with increasing the number of NHC-donor groups. Excited MC states with partial charge transfer to the NHC-donor groups are higher in energy than comparable states without these contributions. The presence of the low-lying MC states prevents the formation of long-lived MLCT states.</div>

scholarly journals The Effect of N-Heterocyclic Carbene Units on the Absorption Spectra of Fe(II) Complexes: A Challenge for Theory

2020 ◽  
Author(s):  
Olga S. Bokareva ◽  
Omar Baig ◽  
Mohamed Al-Marri ◽  
Oliver Kühn ◽  
Leticia Gonzalez
Keyword(s):  
Charge Transfer ◽  
Absorption Spectra ◽  
Excited States ◽  
Partial Charge Transfer ◽  
Polypyridyl Ligands ◽  
Electronic Excited States ◽  
Heteroleptic Complexes ◽  
Ligand Charge Transfer ◽  
Exact Exchange ◽  
Triplet Excited States

<div>The absorption spectra of five Fe(II) homoleptic and heteroleptic complexes containing strong sigma-donating N-heterocyclic carbene (NHC) and polypyridyl ligands have been theoretically characterized using a tuned range-separation functional.</div><div>From a benchmark comparison of the obtained results against other functionals and a multiconfigurational reference, it is concluded that none of the methods is completely satisfactory to describe the absorption spectra.</div><div>Using a compromised choice of 20\% exact exchange, the electronic excited states underlying the absorption spectra are analyzed.</div><div>The low-lying energy band of all the compounds shows predominant metal-to-ligand charge transfer (MLCT) character while the triplet excited states have metal-centered (MC) nature, which becomes more pronounced with increasing the number of NHC-donor groups. Excited MC states with partial charge transfer to the NHC-donor groups are higher in energy than comparable states without these contributions. The presence of the low-lying MC states prevents the formation of long-lived MLCT states.</div>

Excited State Tracking During the Relaxation of Coordination Compounds

2018 ◽  
Author(s):  
Juan Sanz García ◽  
Martial Boggio-Pasqua ◽  
Ilaria Ciofini ◽  
Marco Campetella
Keyword(s):  
Excited State ◽  
Excited States ◽  
Potential Energy Surfaces ◽  
Photochemical Reactions ◽  
Complex Nature ◽  
Electronic Excited States ◽  
Ruthenium Nitrosyl ◽  
State Tracking ◽  
Energy Surfaces ◽  
Electronic Wavefunction

<div>The ability to locate minima on electronic excited states (ESs) potential energy surfaces (PESs) both in the case of bright and dark states is crucial for a full understanding of photochemical reactions. This task has become a standard practice for small- to medium-sized organic chromophores thanks to the constant developments in the field of computational photochemistry. However, this remains a very challenging effort when it comes to the optimization of ESs of transition metal complexes (TMCs), not only due to the presence of several electronic excited states close in energy, but also due to the complex nature of the excited states involved. In this article, we present a simple yet powerful method to follow an excited state of interest during a structural optimization in the case of TMC, based on the use of a compact hole-particle representation of the electronic transition, namely the natural transition orbitals (NTOs). State tracking using NTOs is unambiguously accomplished by computing the mono-electronic wavefunction overlap between consecutive steps of the optimization. Here, we demonstrate that this simple but robust procedure works not only in the case of the cytosine but also in the case of the ES optimization of a ruthenium-nitrosyl complex which is very problematic with standard approaches.</div>

Electronic absorption, fluorescence and polarisation spectra of α,β-diamino-9,10-anthraquinones and their interpretation by the method of configuration analysis

1982 ◽  
Vol 47 (10) ◽  
pp. 2604-2614 ◽  
Author(s):  
Miloš Nepraš ◽  
Miloš Titz ◽  
Jürgen Fabian ◽  
Bohuslav Gaš
Keyword(s):  
Polyvinyl Alcohol ◽  
Absorption Spectra ◽  
Excited States ◽  
Wavelength Range ◽  
Electronic Absorption ◽  
Frequency Dependent ◽  
Absorption Frequency

On the basis of measurement of absorption frequency-dependent polarisation spectra of fluorescence (APF) and dichroism on oriented polyvinyl alcohol sheets, interpretation has been carried out of absorption spectra of α,β-diamino-9,10-anthraquinones in the wavelength range 250 to 600 nm. Character of the excited states has been investigated by the method of configuration analysis (PPP-CA).

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