Here, femtosecond electron diffraction measurements corroborated by atomistic simulations uncover transient lattice deformations accompanying radiationless electronic processes in colloidal semiconductor nanocrystals. Nevertheless, the dynamic structural origins of nonradiative relaxations in such materials are not understood. Nonradiative processes limit optoelectronic functionality of nanocrystals and curb their device performance. N., Saint-Martin, R., Revcolevschi, A., Kemper, A., Schlotter, W., Dakovski, G. W., Johnston, S., Tseng, Y., Rumo, M., Coslovich, G., Zohar, S., Lin, M.
Probing the interplay between lattice dynamics and short-range magnetic correlations in CuGeO3 with femtosecond RIXS NPJ QUANTUM MATERIALS Paris, E., Nicholson, C. Our experiment and simulations unveil the intermolecular character of the water vibration preceding the relaxation of the OH stretch. Molecular dynamics simulations reveal the need to treat the distribution of the shared proton in the hydrogen bond quantum mechanically to capture the structural dynamics on femtosecond timescales. We observed a transient hydrogen bond contraction of roughly 0.04A on a timescale of 80 femtoseconds, followed by a thermalization on a timescale of approximately 1 picosecond. Here, we measure the ultrafast structural response to the excitation of the OH stretching vibration in liquid water with femtosecond temporal and atomic spatial resolution using liquid ultrafast electron scattering. 
However, these experiments cannot directly resolve the motion of the atomic positions and require difficult translation of spectral dynamics into hydrogen bond dynamics. Most existing knowledge of vibrational relaxation in water is built upon ultrafast spectroscopy experiments2-7.
An accurate description of the ultrafast vibrational motion of water molecules is essential for understanding the nature of hydrogen bonds and many solution-phase chemical reactions. Many anomalous properties of liquid water originate from its well-connected hydrogen bond network1, including unusually efficient vibrational energy redistribution and relaxation2. Water is one of the most important, yet least understood, liquids in nature.
Vice Provost for Undergraduate Education. Office of Vice President for Business Affairs and Chief Financial Officer. 
Office of VP for University Human Resources. Stanford Woods Institute for the Environment. Stanford Institute for Economic Policy Research (SIEPR). Institute for Stem Cell Biology and Regenerative Medicine. Institute for Human-Centered Artificial Intelligence (HAI). Institute for Computational and Mathematical Engineering (ICME). Freeman Spogli Institute for International Studies. School of Earth, Energy and Environmental Sciences.
0 kommentar(er)
