Post-orientation free single molecule imaging by XFELs

TL;DR

This paper introduces a novel method for single molecule imaging with XFELs that bypasses the need for orienting diffraction patterns by directly measuring sample orientation through Coulomb explosion fragments.

Contribution

The paper proposes a new approach to determine sample orientation directly from Coulomb explosion fragments, eliminating the challenging orientation process in XFEL single molecule imaging.

Findings

Molecular dynamics simulations validate the method.

Sample orientation can be inferred from fragment angular distribution.

The approach simplifies the imaging process.

Abstract

Single molecule imaging is one of the main target areas of X-ray free electron lasers. It relies on the possibility of orienting the large number of low counting statistics 2D diffraction patterns taken at random orientations of identical replicas of the sample. This is a difficult process and the low statistics limits the usability of orientation methods and ultimately it could prevent single molecule imaging. We suggest a new approach, which avoids the orientation process from the diffraction patterns. In our schema one measures the orientation of the sample together with the diffraction pattern by detecting some fragments of the Coulomb explosion. We show by molecular dynamics simulations that from the angular distribution of the fragments one can obtain the orientation of the samples.