|Budget Amount *help
¥2,700,000 (Direct Cost : ¥2,700,000)
Fiscal Year 1998 : ¥1,000,000 (Direct Cost : ¥1,000,000)
Fiscal Year 1997 : ¥1,700,000 (Direct Cost : ¥1,700,000)
Ultrathin films of n-alkane (1), fatty acid salt (II), alkadiyne (Ill), and alkatetrayne (IV), prepared by vapor- deposition onto a cleavage plane of graphite, were characterized by Penning ionization electron spectra (PIES) and ultraviolet photoelectron spectra (UPS). The PIES showed that a monolayer of laying molecules can be formed with every compound. The UPS indicated that the monolayers are superposed layer by layer. Compounds I-Ill provided, however, slightly different PIES for the mono- and multilayers. Analysis of DOS and local distribution for pseudo-pi and siguma^<2s> MOs revealed the reason : both the long and short axes of the zigzag plane are parallel to the substrate surface in the first layer whereas the short axis becomes tiled a little in the following overlayers.
A monolayer of III, that of sashlike macromolecules (atomic sashes) prepared by intramonolayer photopolymerization (IMPP) of Ill, and a single sheet of a clothlike macromolecule (atomic cloth) prepared by IMPP of IV were investigated by scanning tunneling microscopy (STM). The flat orientation of molecules and/or alkyl chains was confirmed ; their arrangement, commensuration with the substrate, and the periodic structure of the macromolecules were disclosed.
The atomic sashes were superposed layer by layer. It was found that alkyl chains are oriented flat in the multilayers, unlike in the piled-up monolayers of III, although conformational irregularities in the outermost layer were detected by PIES during the superposition. The irregularities were observed in STM images as well for a specimen composed of monolayer (A) and bilayer (A^2) portions : the alkyl ends of the overlayer in an A^2 portion was so unstable that the A-A^2 boundary was observed differently in every image. Except for the boundary, however, the alkyl and polydiacetylene chains in the A^2 portion were arranged regularly as in the A portion but with different lateral orientation.