Quenching Dynamics of Electronically Excited Hydroxyl Radicals
Abstract
Collisional quenching of electronically excited OH A 2-Sigma+ radicals by molecular partners has been investigated over the past 25 years, principally by evaluating the quenching cross sections for partners of aeronautical, atmospheric, and/or combustion relevance. Yet little is known about the outcome of these electronic quenching events, except that they facilitate the efficient removal of OH from the excited A 2-Sigma+ electronic state by introducing nonradiative decay pathways. Most recently, we carried out the first experimental investigation of the nonreactive decay channel with molecular hydrogen by examining the quantum state distribution of the ground state OH X 2-Pi products. The OH X 2-Pi product state distribution is highly nonstatistical, with a strongly inverted rotational distribution for v"=1, demonstrating that a significant torque is applied to OH as purely electronic energy is converted into internal excitation of the OH X 2-Pi products. The high degree of rotational excitation is a direct manifestation of the forces in the vicinity of the conical intersection region(s) that lead to quenching.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jan 19, 2007
- Accession Number
- ADA462945
Entities
People
- Marsha I. Lester
Organizations
- University of Pennsylvania