skip to main content

DOE PAGESDOE PAGES

Title: Coherent X-rays reveal the influence of cage effects on ultrafast water dynamics

Here, the dynamics of liquid water feature a variety of time scales, ranging from extremely fast ballistic-like thermal motion, to slower molecular diffusion and hydrogen-bond rearrangements. Here, we utilize coherent X-ray pulses to investigate the sub-100 fs equilibrium dynamics of water from ambient conditions down to supercooled temperatures. This novel approach utilizes the inherent capability of X-ray speckle visibility spectroscopy to measure equilibrium intermolecular dynamics with lengthscale selectivity, by measuring oxygen motion in momentum space. The observed decay of the speckle contrast at the first diffraction peak, which reflects tetrahedral coordination, is attributed to motion on a molecular scale within the first 120 fs. Through comparison with molecular dynamics simulations, we conclude that the slowing down upon cooling from 328 K down to 253 K is not due to simple thermal ballistic-like motion, but that cage effects play an important role even on timescales over 25 fs due to hydrogen-bonding.
Authors:
ORCiD logo [1] ; ORCiD logo [2] ;  [3] ;  [2] ;  [2] ; ORCiD logo [4] ; ORCiD logo [5] ; ORCiD logo [2] ;  [2] ; ORCiD logo [2] ;  [2] ; ORCiD logo [3] ;  [3] ;  [6] ; ORCiD logo [3] ;  [3] ; ORCiD logo [3] ; ORCiD logo [3] ;  [7] ;  [3] more »;  [3] ;  [3] ; ORCiD logo [3] ;  [3] ;  [3] ; ORCiD logo [3] ;  [5] ; ORCiD logo [2] ;  [2] « less
  1. Stockholm Univ., Stockholm (Sweden); SLAC National Accelerator Lab., Menlo Park, CA (United States)
  2. Stockholm Univ., Stockholm (Sweden)
  3. SLAC National Accelerator Lab., Menlo Park, CA (United States)
  4. KTH Royal Institute of Technology, Stockholm (Sweden)
  5. Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Hamburg Centre for Ultrafast Imaging, Hamburg (Germany)
  6. SLAC National Accelerator Lab., Menlo Park, CA (United States); European XFEL, Schenefeld (Germany)
  7. Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany)
Publication Date:
Grant/Contract Number:
AC02-76SF00515
Type:
Accepted Manuscript
Journal Name:
Nature Communications
Additional Journal Information:
Journal Volume: 9; Journal Issue: 1; Journal ID: ISSN 2041-1723
Publisher:
Nature Publishing Group
Research Org:
SLAC National Accelerator Lab., Menlo Park, CA (United States)
Sponsoring Org:
USDOE
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS
OSTI Identifier:
1458735