Low-Lying Electronic Excited States of Pentacene Oligomers: A Comparative Electronic Structure Study in the Context of Singlet Fission

2014 ◽  
Vol 11 (1) ◽  
pp. 147-156 ◽  
Author(s):  
Pedro B. Coto ◽  
Sahar Sharifzadeh ◽  
Jeffrey B. Neaton ◽  
Michael Thoss
Keyword(s):  
Electronic Structure ◽  
Excited States ◽  
Structure Study ◽  
Singlet Fission ◽  
Electronic Excited States

Electronic structure and spectra of (Cu2O)n–H2O complexes

2015 ◽  
Vol 17 (1) ◽  
pp. 428-433 ◽  
Author(s):  
Ioannis D. Petsalakis ◽  
Giannoula Theodorakopoulos ◽  
Jerry Whitten
Keyword(s):  
Electronic Structure ◽  
Charge Transfer ◽  
Surface Structure ◽  
Excited States ◽  
Electronic Excited States ◽  
Mesh Surface

(Cu2O)n clusters form nanobarrels with a square mesh surface structure. Low-lying charge-transfer electronic excited states of (Cu2O)n–H2O are determined.

scholarly journals Nature of ground and electronic excited states of higher acenes

2016 ◽  
Vol 113 (35) ◽  
pp. E5098-E5107 ◽  
Author(s):  
Yang Yang ◽  
Ernest R. Davidson ◽  
Weitao Yang
Keyword(s):  
Excited States ◽  
Ground State ◽  
Chemical Reactivity ◽  
Random Phase ◽  
Singlet Ground State ◽  
Short Axis ◽  
Singlet Fission ◽  
Shell Side ◽  
Electronic Excited States ◽  
Covalent Nature

Higher acenes have drawn much attention as promising organic semiconductors with versatile electronic properties. However, the nature of their ground state and electronic excited states is still not fully clear. Their unusual chemical reactivity and instability are the main obstacles for experimental studies, and the potentially prominent diradical character, which might require a multireference description in such large systems, hinders theoretical investigations. Here, we provide a detailed answer with the particle–particle random-phase approximation calculation. The 1Ag ground states of acenes up to decacene are on the closed-shell side of the diradical continuum, whereas the ground state of undecacene and dodecacene tilts more to the open-shell side with a growing polyradical character. The ground state of all acenes has covalent nature with respect to both short and long axes. The lowest triplet state 3B2u is always above the singlet ground state even though the energy gap could be vanishingly small in the polyacene limit. The bright singlet excited state 1B2u is a zwitterionic state to the short axis. The excited 1Ag state gradually switches from a double-excitation state to another zwitterionic state to the short axis, but always keeps its covalent nature to the long axis. An energy crossing between the 1B2u and excited 1Ag states happens between hexacene and heptacene. Further energetic consideration suggests that higher acenes are likely to undergo singlet fission with a low photovoltaic efficiency; however, the efficiency might be improved if a singlet fission into multiple triplets could be achieved.

Quantum chemical study of the electronic structure of NiCH2+ in its ground state and low-lying electronic excited states

2005 ◽  
Vol 122 (4) ◽  
pp. 044313 ◽  
Author(s):  
Sébastien Villaume ◽  
Chantal Daniel ◽  
Alain Strich ◽  
S. Ajith Perera ◽  
Rodney J. Bartlett
Keyword(s):  
Electronic Structure ◽  
Excited States ◽  
Ground State ◽  
Quantum Chemical ◽  
Quantum Chemical Study ◽  
Chemical Study ◽  
Electronic Excited States

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>

Unconventional singlet fission materials

2021 ◽  
Author(s):  
Tobias Ullrich ◽  
Dominik Munz ◽  
Dirk M. Guldi
Keyword(s):  
Excited States ◽  
Singlet Fission ◽  
Triplet Excited States

Singlet fission (SF) is a photophysical downconversion pathway, in which a singlet excitation transforms into two triplet excited states.

scholarly journals Electronic Structure Study of Divanadium Complexes with Rigid Covalent Coordination: Potential Molecular Qubits with Slow Spin Relaxation

2021 ◽  
Author(s):  
Stephen Sproules
Keyword(s):  
Electronic Structure ◽  
Spin Relaxation ◽  
Ground State ◽  
Electronic Structures ◽  
Structure Study ◽  
Ligand Shell

The electronic structures of homovalent [V2(μ-S2)2(R2dtc)4] (R = Et, iBu) and mixed-valent [V2(μ-S2)2(R2dtc)4]+ are reported here. The soft-donor, eight-coordinate ligand shell combined with the fully delocalised ground state provides a...

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