Nonadiabatic molecular dynamics simulations for ultrafast photo-induced ring-opening and isomerization reactions of 2,2-diphenyl-2-chromene
Nonadiabatic molecular dynamics simulations with a global switching algorithm have been performed at the TD-CAM-B3LYP-D3/def2-SVP level of theory for ultrafast photo-induced ring-opening and isomerization reactions upon S 1 excitation for 2,2-diphenyl-2 H -chromene (DPC). Both DPC-T and DPC-C confor...
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Veröffentlicht in: | Physical chemistry chemical physics : PCCP 2023-11, Vol.25 (45), p.31363-31373 |
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Zusammenfassung: | Nonadiabatic molecular dynamics simulations with a global switching algorithm have been performed at the TD-CAM-B3LYP-D3/def2-SVP level of theory for ultrafast photo-induced ring-opening and isomerization reactions upon S
1
excitation for 2,2-diphenyl-2
H
-chromene (DPC). Both DPC-T and DPC-C conformers undergo ring-opening relaxation and isomerization pathways accompanied with pyran conformation conserved and converted on the S
1
or S
0
states
via
competition and cooperation between C-O bond dissociation and pyran inversion motions. Upon S
1
excitation, the DPC-T mainly relaxes to the T-type conical intersection region and thus yields a higher ring-opening efficiency with a faster S
1
decay and intermediate formation than those of the DPC-C mainly relaxing to C-type conical intersection. The simulated ring-opening quantum yield for DPC-T (DPC-C) is 0.91 (0.76), which is in good agreement with the experimental value of 0.7-0.9, and the thermal weight averaged lifetimes are estimated as 182.0 fs, 228.6 fs, and 1262.4 fs for the excited-state decay, intermediate formation, and ring-opening product, respectively. These time constants are in good agreement with the experimentally measured
τ
1
time constant of 190-450 fs and
τ
2
time constant of 1000-1800 fs. The present work could be a valuable reference for understanding the nature of the photorelaxation mechanisms of DPC, and could help to develop DPC-based photoresponsive materials.
Potential energy surface profiles for ground state and the first excited-state of 2,2-diphenyl-2
H
-chromene (DPC) including two conical intersections that govern the ring-opening and photoisomerization reaction dynamics of the DPC system. |
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ISSN: | 1463-9076 1463-9084 |
DOI: | 10.1039/d3cp04132h |