Unexpectedly large O37ClO/O35ClO intensity ratios of the fluorescence from the low-energy vibrational levels of OClO (Ã 2A2)

• Published in: The Journal of chemical physics 1999-07, Vol.111 (2), p.456-459
• Main Authors: Lim, Goo-Il, Lim, Soon-Mi, Kim, Sang Kyu, Choi, Young S.
• Format: Article
• Language: English
• ISSN: 0021-9606; 1089-7690
• DOI: 10.1063/1.479325

The fluorescence intensity ratios of O37ClO/O35ClO excited to the Ã 2A2 state have been found to be much larger than that expected from the 37Cl/35Cl natural abundance ratio for several low-energy vibrational levels. For instance, the O37ClO/O35ClO ratios are 1.67 and >10 for the (0,0,0) and (1,1,0) bands, respectively, which are 5 and 30 times larger than those expected from the natural abundance ratio. These unusual isotope effects are observed in a narrow energy region within ∼1000 cm−1 above the electronic origin. It is likely that the isotopomer-selective, near-resonant spin-orbit coupling of the low-energy vibrational levels of the 2A2 state with those of the 2A1 state, which provides a decay channel for the 2A2 state via spin-orbit coupling, is responsible for the unusual isotope effect.