4 research outputs found
A study of product ratios in the direct (313 nm) and Hg-sensitized (254 nm) photodecomposition of 2-methylcyclohexanone in the gas phase
Coherent Motion Reveals Non-Ergodic Nature of Internal Conversion between Excited States
We found that specific nuclear motion along lowâfrequency modes is effective in coupling electronic states and that this motion prevail in some small molecules. Thus, in direct contradiction to what is expected based on the standard models, the internal conversion process can proceed faster for smaller molecules. Specifically, we focus on the S2âS1 internal conversion in cyclobutanone, cyclopentanone, and cyclohexanone. By means of timeâresolved mass spectrometry and photoelectron spectroscopy the relative rate of this transition is determined to be 13:2:1. Remarkably, we observe coherent nuclear motion on the S2 surface in a ringâpuckering mode and motion along this mode in combination with symmetry considerations allow for a consistent explanation of the observed relative timeâscales not afforded by only considering the density of vibrational states or other aspects of the standard models