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Updated: Jan 15, 2026

Spatial Separation of Molecular Conformers and Clusters
Published on: January 9, 2014
Nonadiabatic photodissociation dynamics of indole using multi-configuration time-dependent Hartree method
Soumyadip Ray1, Sudip Sasmal2, Padmabati Mondal1
1Department of Chemistry and Center for Atomic, Molecular, and Optical Sciences and Technologies (CAMOST), Indian Institute of Science Education and Research (IISER), Tirupati, India.
Indole photodissociation dynamics reveal N-H bond fission is controlled by non-adiabatic coupling. This study clarifies the ultrafast N-H stretching dynamics and internal conversion processes in indole.
Area of Science:
- Computational Chemistry
- Chemical Physics
- Photochemistry
Background:
- Indole is a biologically relevant chromophore studied for its photochemical properties.
- Understanding photodissociation dynamics is crucial for various chemical and biological processes.
Purpose of the Study:
- To investigate the N-H photodissociation dynamics of indole using nonadiabatic quantum dynamics.
- To identify key vibrational modes and coupling mechanisms governing indole's photochemistry.
Main Methods:
- Ab initio potential energy cuts (PECs) calculated using multi-state complete active space self-consistent field (XMS-CASSCF) method.
- Construction of a multi-mode multi-state vibronic Hamiltonian.
- Nonadiabatic quantum dynamics simulations using the multi-configuration time-dependent Hartree (MCTDH) method.
Main Results:
- The Q42 normal mode is identified as the most significant for N-H stretching.
- Non-adiabatic coupling between La and π-σ* states is critical for photodissociation.
- Two timescales (26 fs and 113 fs) observed, corresponding to internal conversion and photodissociation.
- Approximately 80% N-H fission probability achieved within 200 fs.
Conclusions:
- The study elucidates the crucial role of non-adiabatic coupling in indole's N-H photodissociation.
- The identified timescales and reaction probabilities align with experimental findings.
- This research provides insights into the photodynamics of large molecules with similar chromophores.
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