CORRECTIONS TO ATOMIC SCATTERING FACTORS FOR HIGH-ENERGY ELECTRONS ARISING FROM ATOMIC VIBRATIONS

Thermal vibrations of the atoms of a crystal result in loss of coheren ce of a fast electron when it enters the crystal. The scattering of th e coherent part of the wave may be modelled by introducing a correctio n to the time-averaged electrostatic potential of the crystal. The cor rection involves both a real part and an imaginary part. The real part is not usually considered in calculations of diffracted intensities b ut for strong scatterers such as An atoms it is sufficiently large tha t it should be measurable by convergent-beam diffraction.