Enhanced reactivity of fluorine with para-hydrogen in cold interstellar clouds by resonance-induced quantum tunnelling.
Nat Chem
; 11(8): 744-749, 2019 Aug.
Article
de En
| MEDLINE
| ID: mdl-31235895
ABSTRACT
Chemical reactions are important in the evolution of low-temperature interstellar clouds, where the quantum tunnelling effect becomes significant. The F + para-H2 â HF + H reaction, which has a significant barrier of 1.8 kcal mol-1, is an important source of HF in interstellar clouds; however, the dynamics of this quantum-tunnelling-induced reactivity at low temperature is unknown. Here, we show that this quantum tunnelling is caused by a post-barrier resonance state. Quantum-state-resolved crossed-beam scattering measurements reveal that this resonance state has a collision energy of ~5 meV and a lifetime of ~80 fs, which are in excellent agreement with a recent anion photoelectron spectroscopic study. Accurate quantum reactive scattering calculations on the new iCSZ-LWAL potential energy surfaces provides a detailed explanation of the experimental results. The reaction rate for this system was also theoretically determined accurately at temperatures as low as 1 K.
Texte intégral:
1
Collection:
01-internacional
Base de données:
MEDLINE
Langue:
En
Journal:
Nat Chem
Sujet du journal:
QUIMICA
Année:
2019
Type de document:
Article
Pays d'affiliation:
Chine