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Updated: Jun 28, 2025
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Measurement of Ultrafast Vibrational Coherences in Polyatomic Radical Cations with Strong-Field Adiabatic Ionization
Published on: August 6, 2018
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Ultrafast Excited-State Nonadiabatic Dynamics in Pt(II) Donor-Bridge-Acceptor Assemblies: A Quantum Approach for
Souvik Mandal1, Chantal Daniel1
1Laboratoire de Chimie Quantique, Institut de Chimie Strasbourg, UMR-7177 CNRS, Université de Strasbourg, 1 Rue Blaise Pascal BP 296/R8, F-67008 Strasbourg, France.
The Journal of Physical Chemistry. A
|April 15, 2024
Summary
Ultrafast dynamics in platinum complexes are driven by spin-vibronic mechanisms. Selective vibrational excitation offers a route to control excited-state populations and photoproducts.
Area of Science:
- Photochemistry and Photophysics
- Quantum Dynamics
- Computational Chemistry
Background:
- Platinum(II) complexes with donor-bridge-acceptor structures are key in light-harvesting and photoredox catalysis.
- Understanding excited-state dynamics is crucial for designing efficient light-driven processes.
Purpose of the Study:
- To investigate the ultrafast nonadiabatic excited-state dynamics of a Pt(II) complex using quantum mechanical methods.
- To elucidate the role of spin-orbit coupling and vibronic coupling in excited-state decay pathways.
- To explore the potential for optical control of photoproduct branching ratios via selective vibrational excitation.
Main Methods:
- Wavepacket propagation simulations using the multiconfiguration time-dependent Hartree (MCTDH) method.
- Electronic structure calculations at the time-dependent density functional theory (TD-DFT) level.
- Inclusion of spin-orbit coupling (SOC) and vibronic coupling in an 11-state multimode model with up to 18 vibrational modes.
Main Results:
- Identified key spin-vibronic mechanisms governing subpicosecond excited-state decay.
- Distinguished between spin-orbit and vibronically activated ultrafast processes.
- Demonstrated that specific vibrational modes, like N-benzyl twisting, can selectively populate charge-separated states over charge-transfer states.
Conclusions:
- Selective excitation of vibrational modes can steer nonadiabatic dynamics and control photoproduct formation.
- This quantum study provides a theoretical basis for infrared optical control experiments.
- The interplay of spin-orbit coupling and vibronic effects is critical in ultrafast dynamics of these Pt(II) complexes.
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