Nonadiabatic dynamics in a forest of coupled states: Electronic state branching in the VUV photodissociation of N2

Natalia Gelfand; Ksenia Komarova; Françoise Remacle; Raphael D Levine

doi:10.1063/5.0148798

Nonadiabatic dynamics in a forest of coupled states: Electronic state branching in the VUV photodissociation of N2

J Chem Phys. 2023 Apr 28;158(16):164302. doi: 10.1063/5.0148798.

Authors

Natalia Gelfand¹, Ksenia Komarova¹, Françoise 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, Los Angeles, California 90095, USA.
⁴ Department of Chemistry and Biochemistry, University of California, Los Angeles, California 90095, USA.

PMID: 37102444
DOI: 10.1063/5.0148798

Abstract

Multi-state electronic dynamics at higher excitation energies is needed for the understanding of a variety of energy rich situations, including chemistry under extreme conditions, vacuum ultraviolet (VUV) induced astrochemistry, and attochemistry. It calls for an understanding of three stages, energy acquisition, dynamical propagation, and disposal. It is typically not possible to identify a basis of uncoupled quantum states that is sufficient for the three stages. The handicap is the large number of coupled quantum states that is needed to describe the system. Progress in quantum chemistry provides the necessary background to the energetics and the coupling. Progress in quantum dynamics takes this as input for the propagation in time. Right now, it seems that we have come of age with potential detailed applications. We here report a demonstration to a coupled electron-nuclear quantum dynamics through a maze of 47 electronic states and with attention to the order in perturbation theory that is indicated using propensity rules for couplings. Close agreement with experimental results for the VUV photodissociation of 14N2 and its isotopomer 14N15N is achieved. We pay special attention to the coupling between two dissociative continua and an optically accessible bound domain. The computations reproduce and interpret the non-monotonic branching between the two exit channels producing N(2D) and N(2P) atoms as a function of excitation energy and its variation with the mass.