Competing quantum tunneling processes of heavy and light particles in isocyanic acid radical anions.

ABSTRACT: Quantum tunneling is known to be mass dependent. Here we report an unexpected mass effect on tunneling reactions in isocyanic acid radical anions (HNCO^•-), which exhibit negative electron affinities. The cis- and trans-isomers of HNCO^•- were generated in a solid neon matrix and their interconversion and electron-detachment tunneling kinetics were investigated using infrared absorption spectroscopy. The results reveal that electron tunneling, which involves some degree of nuclear motion of HNCO^•- to neutral HNCO, occurs at a slower rate than the cis-to-trans isomerization of HNCO^•-, with the latter following a distinct bond angle inversion pathway driven by the heavy carbon atom. This contrasts to the typical dominance of light hydrogen atom tunne

SUBMITTER: Tang J 

PROVIDER: S-EPMC12660882 | biostudies-literature | 2025 Nov

REPOSITORIES: biostudies-literature