How to realize an ultrafast electron diffraction experiment with a terahertz pump: a theoretical study

To integrate a terahertz pump into an ultrafast electron diffraction (UED) experiment has attracted much attention due to its potential to initiate and detect the structural dynamics both directly. However, the deflection of the electron probe by the electromagnetic field of the terahertz pump alters the incident angle of the electron probe on the sample, impeding it from recording structural information afterwards. In this article, we studied this issue by a theoretical simulation of the terahertz-induced deflection effect on the electron probe, and came up with several possible schemes to reduce such effect. As a result, a terahertz-pump-electron-probe UED experiment with a temporal resolution comparable to the terahertz period is realized. We also found that MeV UED was more suitable for such terahertz pump experiment.

The Stripe of Electron Diffraction in Magnetic Field—A Counterexample. In Electric Field, the Result Will Be the Same

As long as no one has done diffraction experiment in the spark chamber (DESC) , it makes sense to do this experiment. This experiment has two possible results: (1) Diffraction fringes cannot be obtained; (2) Path information and diffraction patterns can be obtained at the same time. If the result is (1), it provides direct and unambiguous experimental evidence for the existing Copenhagen quantum mechanics interpretation system, which can avoid some unnecessary disputes; If the result is (2), it will cause a scientific revolution in the field of quantum mechanics interpretation (After all, most people now think that "as long as the particle path is observed in the double slit experiment, the interference fringes will disappear"). "The result of the electron diffraction experiment in a magnetic field—diffraction fringes can still be obtained" was discovered. This finding provides an experimental evidence for DESC to be meaningful and predicts that the experimental result of DESC is the result (2).

Structure solution of the new titanate Li4Ti8Ni3O21 using precession electron diffraction

A sample having stoichiometry Li[Ti1.5Ni0.5]O4 has been synthesized to obtain a spinel structure. The resulting crystalline powder revealed a multiphase nature with spinel as the minor phase. The main phase is a new trigonal phase having a = 5.05910 (1), c = 32.5371 (1) Å. The structure has been solved by direct methods working on a three-dimensional set of intensities obtained from a precession electron-diffraction experiment, and refined on synchrotron powder diffraction data in the space group P\bar 3c1. The model consists of hexagonal layers of edge-sharing octahedra occupied either by the heavy cations Ti and Ni, or preferentially by Li. On the basis of cation-site occupancies the stoichiometry becomes Li4Ti8Ni3O21, which is compatible with the microanalysis results.

Single Shot Electron Diffraction Experiment Using a Sub ps MeV Electron Source

Extended abstract of a paper presented at Microscopy and Microanalysis 2006 in Chicago, Illinois, USA, July 30 – August 3, 2005