Simulating Images of Thin Specimens
This chapter discusses the calculation of an electron microscope image neglecting the geometrical thickness of the specimen (i.e., very thin specimens). Many practical specimens are too thick for this type of calculation to be quantitatively correct. However this approach can provide a qualitative insight into the structure in the image and it requires much less computer time. This type of image simulation is sometimes referred to as a phase grating approximation or a kinematical image approximation because it does not properly include the effects of multiple or plural scattering within the specimen. Calculation of the transmission function of thin specimens is also a necessary part of more advanced calculations including a realistic specimen thickness that will be considered in later chapters. In particular the calculation presented in this chapter will form a single slice of the multislice algorithm
KeywordsReciprocal Space Single Atom Transmission Function Spherical Aberration Atomic Potential
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