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Published on: January 19, 2018
Reverse Intersystem Crossing Dynamics in Vibronically Modulated Inverted Singlet-Triplet Gap System: A Wigner Phase
Pijush Karak1, Pradipta Manna1, Ambar Banerjee2
1Department of Chemistry, University of Calcutta, 92 A. P. C. Road, Kolkata 700009, West Bengal, India.
The inverted singlet-triplet gap (INVEST) and reverse intersystem crossing (rISC) rate depend on molecular geometry. Nuclear motion, specifically puckering, is crucial for observing INVEST and its temperature-dependent rISC dynamics.
Area of Science:
- Photochemistry
- Quantum Chemistry
- Molecular Dynamics
Background:
- Recent observations show an inverted singlet-triplet gap (INVEST) and slow changes in reverse intersystem crossing (rISC) rates with temperature.
- Understanding the origins of these phenomena is crucial for controlling photophysical processes.
Purpose of the Study:
- To investigate the origin of the inverted singlet-triplet gap (INVEST).
- To explore the reasons behind the slow temperature dependence of the reverse intersystem crossing (rISC) rate.
- To elucidate the role of nuclear degrees of freedom in these processes.
Main Methods:
- Utilized Wigner phase space studies.
- Analyzed equilibrium and non-equilibrium geometries.
- Investigated variations in exchange interaction and double excitations.
Main Results:
- The inverted singlet-triplet gap (INVEST) is present at equilibrium geometry.
- Deviations from equilibrium, within the harmonic region, lead to non-INVEST behavior due to changes in exchange interaction and double excitations.
- Nuclear degrees of freedom, particularly geometric puckering, significantly influence INVEST and rISC dynamics.
Conclusions:
- The inverted singlet-triplet gap (INVEST) is not solely determined by equilibrium geometry.
- Nuclear motion and molecular geometry play a critical role in the observed INVEST and temperature-dependent rISC rates.
- Geometric puckering is identified as a key factor governing INVEST and associated rISC dynamics.
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