Practical crystallography with a transmission electron microscope

Area of Science:

• Materials Science and Crystallography
• Electron Microscopy and Diffraction

Background:

• Three-dimensional electron diffraction (3DED) is crucial for solving crystal structures of sub-micron crystals, particularly those too small for X-ray diffraction.
• Wider adoption of 3DED has been hindered by the need for specialized transmission electron microscopes (TEMs) with custom software for data acquisition.
• Existing software solutions for 3DED are often incompatible with various instrument setups, further limiting accessibility.

Purpose of the Study:

• To develop a novel DigitalMicrograph script, GiveMeED, to facilitate controlled and reproducible 3DED data acquisition on conventional TEM systems.
• To establish a comprehensive experimental workflow integrating 3DED with TEM imaging and spectroscopy for correlative analysis.
• To promote wider utilization of 3DED by making the script freely available and compatible with standard workflows.

Main Methods:

• Development and implementation of the GiveMeED script for automated sample rotation and electron diffraction data collection in a TEM.
• Integration of direct imaging, energy-dispersive X-ray spectroscopy (EDS), and electron energy loss spectroscopy (EELS) for correlative characterization.
• Precise control and quantification of electron flux throughout the experimental workflow to minimize beam damage and maintain near-native sample states.

Main Results:

• Successful structure solutions were achieved for paracetamol, copper(II) phthalocyanine, and perchlorocoronene using the GiveMeED script and standard crystallographic software.
• Determined unit cell parameters and atomic connectivity closely matched established X-ray diffraction data, validating the accuracy of the 3DED method.
• The workflow demonstrated effective correlative descriptions of crystal morphologies and sample compositions under controlled low-dose conditions.

Conclusions:

• The GiveMeED script significantly simplifies and standardizes the process of 3DED data acquisition on conventional TEMs.
• This work enables routine crystallographic processing using established single-crystal X-ray diffraction (SCXRD) techniques, making 3DED more accessible.
• The freely available GiveMeED script and described workflow advance the routine application of electron diffraction for crystal structure solution.