2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/161432Point contact spectroscopy on a H2O molecule bridging Pt electrodes reveals a clear crossover between enhancement and reduction of the conductance due to electron-vibration interaction. As single channel models predict such a crossover at transmission probability of t=0.5, we used shot noise measurements to analyze the transmission and observed at least two channels across the junction where the dominant channel has t=0.51+/-0.01 transmission probability at the crossover conductance, which is consistent with the predictions for single-channel models.4 pages, 1 table, 4 figuresMesoscale and Nanoscale PhysicsOther Condensed Mattertext