Orbiting resonances in formaldehyde reveal coupling of roaming, radical, and molecular channels.
Science
; 374(6571): 1122-1127, 2021 Nov 26.
Article
em En
| MEDLINE
| ID: mdl-34822294
ABSTRACT
The roaming chemical reaction mechanism involves near-dissociation of an energized molecule to radicals that leads instead to intramolecular reaction after reorientation at long range. Surprisingly, no clear quantum signatures of roaming have been observed to date, despite the quantum nature of the roaming event. We found evidence of quantum dynamics in the photodissociation of formaldehyde near the roaming threshold. This is ascribed to resonances associated to H+HCO(Ka = 1) that have a profound impact on the CO rotational and translational energy distributions and cause the roaming fraction to vary by a factor of 2 over an energy range of 10 cm1. The roaming pathway serves both to modulate and report on the complex vibrational dynamics and coupling among the three dissociation pathways in the excited molecule as it decays to products.
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Coleções:
01-internacional
Base de dados:
MEDLINE
Idioma:
En
Revista:
Science
Ano de publicação:
2021
Tipo de documento:
Article