光学ポテンシャル

optical potential

[目次：理論(電子の散乱／回折／結像)]

入射線が吸収される効果を取り入れるために虚数部を加えた複素ポテンシャルのこと。電顕像を動力学理論によって説明する際、複素ポテンシャルを使う。複素ポテンシャルの虚数部を与える吸収効果にはプラズモン励起、熱散漫散乱、一電子励起がある。プラズモン散乱は平均吸収に、熱散漫散乱は異常吸収に効く。一電子励起の吸収への寄与は僅かである。

A potential to which the imaginary part is added to incorporate the effect of absorption of an incident beam in a specimen. In the explanation of a TEM image using the dynamical theory, the optical potential is used. The absorption effect which gives the imaginary part of the potential includes plasmon excitation, thermal diffuse scattering and single-electron excitation. Plasmon excitation contributes to the average (normal) absorption and thermal diffuse scattering to the anomalous absorption. Single-electron excitation gives little effect to the anomalous absorption comparing to thermal diffuse scattering.