Jun 14 – 16, 2023
AlbaNova Main Building
Europe/Stockholm timezone

Excited State Dynamics in the Photolysis of Phenyl azide

Not scheduled
20m
Oskar Klein Auditorium FR4 (AlbaNova Main Building)

Oskar Klein Auditorium FR4

AlbaNova Main Building

Roslagstullsbacken 21, 114 21 Stockholm
Poster Sektionen för atom-, molekyl- och optisk fysik Sektionen för atom-, molekyl- och optisk fysik

Speaker

Sambit Kumar Das (Stockholm University)

Description

The photolysis of aryl azides is widely used to produce highly reactive aryl nitrenes, an active intermediate in organic and inorganic synthesis. Phenyl azide (Ph-N$_3$) is considered a model system for a class of aryl azides. The photoproducts of phenyl azide have applications in various fields, e.g., photoaffinity labeling of enzymes, and preparation of electrically conducting polymers$^{[1]}$, while the involved mechanism is of inherent interest from the perspective of quantum chemistry. This piece of work is focused on simulating the ultrafast dynamics involved in the photo-induced N2 dissociation of phenyl azide (Ph-N$_a$-N$_b$-N$_c$), leading to the formation of phenyl nitrene (Ph-N) and Nitrogen molecule (N$_2$).

The excited states and decay dynamics are studied with Complete Active Space Self Consistent Field (CASSCF) and complementary N-Electron Valence State Perturbation Theory (NEVPT2) calculations. Initial investigations from the potential energy surface scans motivated us towards large-scale Molecular Dynamics (MD) simulations to generate a statistical overview of the excited state dynamics. Excited state MD simulations are carried out within the SHARC package from the singlet excited states S$_1$, S$_2$, S$_3$, S$_4$, and S$_5$, acting as initial states. The studies of the simulated trajectories reveal an average dissociation time of 20-40 fs depending on the state from which the excited state simulation initiates. The electronic structure analysis is complemented with investigations on structural dynamics, for a complete illustration of the dissociation procedure. The population analysis of the trajectories presents that irrespective of the initial state, it is the S$_2$ state (a π/π* state) in which the N$_a$-N$_b$ bond splits followed by Nitrene formation. Analysis of the trajectories reveals a direct correlation between the splitting of the N$_a$-N$_b$ bond and the N$_a$-N$_b$-N$_c$ bond angle which takes the dynamics beyond the single degree of freedom framework.

[1] Nina P. Gritsan, Zhendong Zhu, Christopher M. Hadad, and Matthew S. Platz, $\textit{J. Am. Chem. Soc.}$, 3118 (2014) 1999, 121, 6, 1202-1207.

[2] Weston Thatcher Border, Nina P. Gritsan, Christopher M. Hadad, William L. Karney, Carl R. Kemnitz, and Matthew S. Platz, $\textit{Acc. Chem. Res.}$, 2000, 33,11, 765-771

[3] Juan Soto, and Juan C. Otero, $\textit{J. Phys. Chem. A}$, 2019, 123, 9053-9060

Primary author

Sambit Kumar Das (Stockholm University)

Co-authors

Ambar Banerjee (Stockholm University) Michael Odelius (Stockholm University)

Presentation materials

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