Heavy-atom tunnelling in singlet oxygen deactivation predicted by instanton theory with branch-point singularities.

ABSTRACT: The reactive singlet state of oxygen (O₂) can decay to the triplet ground state nonradiatively in the presence of a solvent. There is a controversy about whether tunnelling is involved in this nonadiabatic spin-crossover process. Semiclassical instanton theory provides a reliable and practical computational method for elucidating the reaction mechanism and can account for nuclear quantum effects such as zero-point energy and multidimensional tunnelling. However, the previously developed instanton theory is not directly applicable to this system because of a branch-point singularity which appears in the flux correlation function. Here we derive a new instanton theory for cases dominated by the singularity, leading to a new picture of tunnelling in nonadiabatic processes. Together

SUBMITTER: Ansari IM 

PROVIDER: S-EPMC11522392 | biostudies-literature | 2024 May

REPOSITORIES: biostudies-literature