- Journal Article
Rights / licenseCreative Commons Attribution-NonCommercial 3.0 Unported
Using vacuum-ultraviolet time-resolved velocity map imaging of photoelectrons, we study ultrafast coupled electronic and nuclear dynamics in low-lying Rydberg states of ammonia. Vibrationally-resolved internal vibrational relaxation (IVR) is observed in a progression of the e′ bending modes. This vibrational progression is only observed in the D∼ state, and is lost upon ultrafast internal conversion to the C∼ and B∼ electronic states. Due to the ultrashort time scale of the internal conversion (ca. 64 fs), and the vibronic resolution, the non-adiabatic coupling vectors are identified and verified with ab initio calculations. The time-scale of this IVR process is highly surprising and significant because IVR is usually treated as an incoherent process that proceeds statistically, according to a “Fermi's Golden Rule”-like model, where the process scales with the available degrees of freedom. Here, we show that it can be highly non-statistical, restricted to only a very small subset of vibrational motions. Show more
Journal / seriesPhysical Chemistry Chemical Physics
Pages / Article No.
PublisherRoyal Society of Chemistry
Organisational unit03888 - Wörner, Hans Jakob / Wörner, Hans Jakob
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