Dose symmetric electron diffraction tomography (DS-EDT): Implementation of a dose-symmetric tomography scheme in 3D...

Area of Science:

• Materials Science
• Crystallography
• Electron Microscopy

Background:

• Beam-sensitive nanomaterials (zeolites, MOFs) pose challenges for crystallographic structure determination due to radiation damage.
• Electron diffraction is crucial for analyzing sub-micrometer particles, but low doses reduce data quality.
• Existing 3D electron diffraction techniques struggle with balancing dose reduction and data completeness.

Purpose of the Study:

• To develop a novel method for high-quality structure determination of beam-sensitive nanomaterials.
• To reduce cumulative radiation damage to individual crystals during data acquisition.
• To enable accurate crystallographic analysis of delicate materials using electron diffraction.

Main Methods:

• Developed dose symmetric electron diffraction tomography (DS-EDT) by combining low-dose electron diffraction tomography (LD-EDT) with dose-symmetric schemes from cryo-EM.
• Partitioned electron dose over multiple crystals to minimize damage to any single crystal.
• Merged datasets from individual crystals to achieve complete diffraction data.

Main Results:

• Demonstrated that merging data from small reciprocal space domains is sufficient for reliable structure solution and refinement.
• Obtained high-quality data from a few frames of beam-sensitive manganese formate, while damaged frames aided orientation and unit cell determination.
• Dynamical refinement showed high accuracy in atom positions, validating the DS-EDT method.

Conclusions:

• DS-EDT significantly reduces the total electron dose on individual crystals by up to an order of magnitude compared to LD-EDT.
• This method facilitates accurate crystallographic structure determination and refinement of beam-sensitive nanomaterials.
• DS-EDT offers a powerful approach for analyzing delicate crystalline samples that were previously difficult to study.