Low Dose X-Ray Speckle Visibility Spectroscopy Reveals Nanoscale Dynamics in Radiation Sensitive Ionic Liquids
Artikel i vetenskaplig tidskrift, 2018

X-ray radiation damage provides a serious bottleneck for investigating microsecond to second dynamics on nanometer length scales employing x-ray photon correlation spectroscopy. This limitation hinders the investigation of real time dynamics in most soft matter and biological materials which can tolerate only x-ray doses of kGy and below. Here, we show that this bottleneck can be overcome by low dose x-ray speckle visibility spectroscopy. Employing x-ray doses of 22-438 kGy and analyzing the sparse speckle pattern of count rates as low as 6.7×10-3 per pixel, we follow the slow nanoscale dynamics of an ionic liquid (IL) at the glass transition. At the prepeak of nanoscale order in the IL, we observe complex dynamics upon approaching the glass transition temperature TG with a freezing in of the alpha relaxation and a multitude of millisecond local relaxations existing well below TG. We identify this fast relaxation as being responsible for the increasing development of nanoscale order observed in ILs at temperatures below TG.

Författare

Jan Verwohlt

Universität Siegen

Mario Reiser

European XFEL

Universität Siegen

Lisa Randolph

Universität Siegen

Aleksandar Matic

Chalmers, Fysik, Kondenserade materiens fysik

Luis Aguilera Medina

Chalmers, Fysik, Kondenserade materiens fysik

A. O. Madsen

European XFEL

Michael Sprung

Deutsches Elektronen-Synchrotron (DESY)

Alexey Zozulya

European XFEL

Deutsches Elektronen-Synchrotron (DESY)

Christian Gutt

Universität Siegen

Physical Review Letters

0031-9007 (ISSN) 1079-7114 (eISSN)

Vol. 120 16 168001

Ämneskategorier

Astronomi, astrofysik och kosmologi

Atom- och molekylfysik och optik

Annan fysik

DOI

10.1103/PhysRevLett.120.168001