TEM observation of lattice plane expansion at the surface of a molecular crystal Br8Cl8-Cu-phthalocyanine.
Generally, structures of molecular crystals have imperfections and are therefore rather complex. One kind of imperfection is an expansion of the distance between molecular planes that occurs near a crystal surface. Although such an expansion is often observed in a high-resolution image, it has not been measured quantitatively because of the low signal-to-noise ratio of such images. This problem is due to the sensitivity of molecular crystals to electron doses. Here, we have taken photographs of a crystal surface under high magnification in so far as the dose does not destroy the crystal structure. We have quantitatively measured the distance expansion based on image processing and statistical analysis of many photographs. As a result, we have confirmed that the first and second molecular planes shift towards the outside of a crystal in sub-angstrom order.
Moriguchi
Sakumi
S
Institute for Chemical Research, Kyoto University, Uji, Kyoto 611-0011, Japan. smo@eels.kuicr.kyoto-u.ac.jp
Isoda
Seiji
S
Kobayashi
Takashi
T