Recombination of N Atoms in a Manifold of Electronic States Simulated by Time-Reversed Nonadiabatic Photodissociation Dynamics of N2

Natalia Gelfand; Francoise Remacle; Raphael D Levine

doi:10.1021/acs.jpclett.3c00666

Recombination of N Atoms in a Manifold of Electronic States Simulated by Time-Reversed Nonadiabatic Photodissociation Dynamics of N₂

J Phys Chem Lett. 2023 May 18;14(19):4625-4630. doi: 10.1021/acs.jpclett.3c00666. Epub 2023 May 11.

Authors

Natalia Gelfand¹, Francoise Remacle^{1

2}, Raphael D Levine^{1

3

4}

Affiliations

¹ The Fritz Haber Center for Molecular Dynamics, Institute of Chemistry, The Hebrew University of Jerusalem, Jerusalem 91904, Israel.
² Theoretical Physical Chemistry, UR MolSys B6c, University of Liège, B4000 Liège, Belgium.
³ Department of Molecular and Medical Pharmacology, David Geffen School of Medicine, University of California, Los Angeles, California 90095, United States.
⁴ Department of Chemistry and Biochemistry, University of California, Los Angeles, California 90095, United States.

Abstract

Following a single photon VUV absorption, the N₂ molecule dissociates into distinct channels leading to N atoms of different reactivities. The optically accessible singlets are bound, and dissociation occurs through spin-orbit induced transfer to the triplets. There is a forest of coupled electronic states, and we here aim to trace a path along the nonadiabatic couplings toward a particular exit channel. To achieve this, we apply a time-reversed quantum dynamical approach that corresponds to a dissociation running back. It begins with an atom-atom relative motion in a particular product channel. Starting with a Gaussian wave packet at the dissociation region of N₂ and propagating it backward in time, one can see the population transferring among the triplets due to a strong nonadiabatic interaction between these states. Simultaneously, the optically active singlets get populated because of spin-orbit coupling to the triplets. Thus, backward propagation traces the nonradiative association of nitrogen atoms.