scholarly journals Non-adiabatic and intersystem crossing dynamics in SO2. II. The role of triplet states in the bound state dynamics studied by surface-hopping simulations

2014 ◽  
Vol 140 (20) ◽  
pp. 204302 ◽  
Author(s):  
Sebastian Mai ◽  
Philipp Marquetand ◽  
Leticia González
Keyword(s):  
Bound State ◽  
Intersystem Crossing ◽  
Triplet States ◽  
Surface Hopping

scholarly journals Aggregation Induced Emission in the Tetraphenylthiophene Crystal: The Role of Triplet States

2020 ◽  
Author(s):  
Ljiljana Stojanovic ◽  
Rachel Crespo Otero
Keyword(s):  
Solid State ◽  
Potential Energy Surfaces ◽  
Special Focus ◽  
Intersystem Crossing ◽  
Triplet States ◽  
Aggregation Induced Emission ◽  
The Family ◽  
Energy Surfaces ◽  
Potential Use

<p>Propeller-shaped molecules have received much attention due to their enhanced emission in the condensed phase (Aggregation Induced Emission, AIE) and their potential use in optoelectronic devices. In this contribution, we examine the excited state mechanisms of tetraphenyl-thiophene (TPT), one member of the family which features weaker AIE. We perform a detailed analysis of the potential energy surfaces with special focus on the role of triplet states considering the crystal structure, intermolecular interactions, exciton couplings and reorganisation energies in the vacuum and solid state. In contrast with other members of the propeller-shaped family, nonradiative decay in TPT is driven by bond breaking. Because of the significant spin-orbit couplings along the reaction coordinate, intersystem crossing plays an important role in the mechanism. Our calculations show that aggregation in the solid state hampers the access to internal conversion pathways, however, intersystem crossing is active in the crystal phase, which explains the weak AIE of this molecule. This new understanding of the role of triplet states on the relaxation mechanisms of AIEgens has implications for the design of solid state highly-emissive materials based on TPT.<br></p>

scholarly journals Ultrafast intersystem crossing dynamics in uracil unravelled byab initiomolecular dynamics

2014 ◽  
Vol 16 (44) ◽  
pp. 24423-24436 ◽  
Author(s):  
Martin Richter ◽  
Sebastian Mai ◽  
Philipp Marquetand ◽  
Leticia González
Keyword(s):  
Uv Light ◽  
Intersystem Crossing ◽  
Triplet States ◽  
Surface Hopping

Surface hopping simulations of the RNA nucleobase uracil show that intersystem crossing and hence triplet states play an important role during the photorelaxation after excitation with UV light.

scholarly journals Aggregation Induced Emission in the Tetraphenylthiophene Crystal: The Role of Triplet States

2020 ◽  
Author(s):  
Ljiljana Stojanovic ◽  
Rachel Crespo Otero
Keyword(s):  
Solid State ◽  
Potential Energy Surfaces ◽  
Special Focus ◽  
Intersystem Crossing ◽  
Triplet States ◽  
Aggregation Induced Emission ◽  
The Family ◽  
Energy Surfaces ◽  
Potential Use

<p>Propeller-shaped molecules have received much attention due to their enhanced emission in the condensed phase (Aggregation Induced Emission, AIE) and their potential use in optoelectronic devices. In this contribution, we examine the excited state mechanisms of tetraphenyl-thiophene (TPT), one member of the family which features weaker AIE. We perform a detailed analysis of the potential energy surfaces with special focus on the role of triplet states considering the crystal structure, intermolecular interactions, exciton couplings and reorganisation energies in the vacuum and solid state. In contrast with other members of the propeller-shaped family, nonradiative decay in TPT is driven by bond breaking. Because of the significant spin-orbit couplings along the reaction coordinate, intersystem crossing plays an important role in the mechanism. Our calculations show that aggregation in the solid state hampers the access to internal conversion pathways, however, intersystem crossing is active in the crystal phase, which explains the weak AIE of this molecule. This new understanding of the role of triplet states on the relaxation mechanisms of AIEgens has implications for the design of solid state highly-emissive materials based on TPT.<br></p>

Role of Triplet States in the Photodynamics of Aniline

2021 ◽  
Vol 143 (15) ◽  
pp. 5878-5889
Author(s):  
Aleksandr O. Lykhin ◽  
Donald G. Truhlar ◽  
Laura Gagliardi
Keyword(s):  
Triplet States

scholarly journals The role of spin in the degradation of organic photovoltaics

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Ivan Ramirez ◽  
Alberto Privitera ◽  
Safakath Karuthedath ◽  
Anna Jungbluth ◽  
Johannes Benduhn ◽  
...  
Keyword(s):  
Transient Absorption ◽  
Bulk Heterojunction ◽  
Critical Factor ◽  
Model Systems ◽  
Transient Absorption Spectroscopy ◽  
Triplet States ◽  
Paramagnetic Resonance ◽  
Time Resolved ◽  
A Charge

AbstractStability is now a critical factor in the commercialization of organic photovoltaic (OPV) devices. Both extrinsic stability to oxygen and water and intrinsic stability to light and heat in inert conditions must be achieved. Triplet states are known to be problematic in both cases, leading to singlet oxygen production or fullerene dimerization. The latter is thought to proceed from unquenched singlet excitons that have undergone intersystem crossing (ISC). Instead, we show that in bulk heterojunction (BHJ) solar cells the photo-degradation of C60 via photo-oligomerization occurs primarily via back-hole transfer (BHT) from a charge-transfer state to a C60 excited triplet state. We demonstrate this to be the principal pathway from a combination of steady-state optoelectronic measurements, time-resolved electron paramagnetic resonance, and temperature-dependent transient absorption spectroscopy on model systems. BHT is a much more serious concern than ISC because it cannot be mitigated by improved exciton quenching, obtained for example by a finer BHJ morphology. As BHT is not specific to fullerenes, our results suggest that the role of electron and hole back transfer in the degradation of BHJs should also be carefully considered when designing stable OPV devices.

REDUCED MULTIREFERENCE COUPLED-CLUSTER METHOD AND ITS APPLICATION TO THE PYRIDYNE DIRADICALS

2008 ◽  
Vol 07 (04) ◽  
pp. 805-820 ◽  
Author(s):  
XIANGZHU LI ◽  
JOSEF PALDUS
Keyword(s):  
Molecular Geometry ◽  
External Source ◽  
Cluster Method ◽  
Coupled Cluster ◽  
Triplet States ◽  
Correlation Effects ◽  
Spin Multiplicity ◽  
Triplet Splitting ◽  
Singlet And Triplet States

The reduced multireference (RMR) coupled-cluster (CC) method with singles and doubles (RMR CCSD) that employs a modest-size MR CISD wave function as an external source for the most important (primary) triples and quadruples in order to account for the nondynamic correlation effects in the presence of quasidegeneracy, and which is further perturbatively corrected for the remaining (secondary) triples, RMR CCSD(T), is employed to compute the molecular geometry and the energy of the lowest-lying singlet and triplet states, as well as the corresponding singlet–triplet splitting, for all possible isomers of the m, n-pyridyne diradicals. A comparison is made with earlier results that were obtained by other authors, and the role of the multireference effects for both the geometry and the spin multiplicity of the lowest state, as described by the RMR-type methods, is demonstrated on the example of 2,6- and 3,5-pyridynes.

scholarly journals Intersystem crossing rates of single perylene molecules in ortho-dichlorobenzene

2016 ◽  
Vol 18 (26) ◽  
pp. 17655-17659 ◽  
Author(s):  
Nico R. Verhart ◽  
Pedro Navarro ◽  
Sanli Faez ◽  
Michel Orrit
Keyword(s):  
Optical Switching ◽  
Intersystem Crossing ◽  
Triplet States ◽  
Spin States ◽  
Molecular Fluorescence

Triplet states can be interesting for optical switching of molecular fluorescence as well as quantum experiments relying on the manipulation of spin states.

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