Pseudo-two dimensional films/pseudo-one dimensional wire of metals and fullerene studied by positron annihilation spectroscopy.

1996 Fiscal Year Final Research Report Summary

• Project/Area Number: 07650759
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: Physical properties of metals
• Research Institution: Tokyo Gakugei University
• Principal Investigator: MURAKAMI Hideoki Tokyo Gakugei University, Faculty of Education, Professor, 教育学部, 教授 (30011000)
• Project Period (FY): 1995 – 1996
• Keywords: Positron annihilation / Positronium / Porous materials / fullerene

Research Abstract

The purposes of this study is to clarify the physical and chemical properties of thin films deposited on the micro-pore surfaces and those of thin wires packed in the micro pores of porous materials. Results are :
1. The positronium yield and lifetime were measured on the potassium thin films deposited on the pore surfaces of a micro porous glass. The positronium intensity was decreased from 20% to 3%, and its lifetime was lengthened from 1.3ns to 6.0ns with the deposition of the film.
2. The formation rate and lifetime of positroniums after packing of potassium metal into pores were close to those before the packing. We conclude that the positroniums are formed in the glass and they are not ejected into the pores.
3. The measurements of positron lifetime and Doppler broadening were carried out on the nicro porous glass absorbing liquid benzene. The amount of benzene evaporation was obtained from the lifetime and line-shape parameter.
4. Brominated fullerene was synthesized. The Doppler spectra for the brominated fullerene showed that the positron annihilate preferentially in the interstitial sites among the fullerene molecules.
5. Alkali metals were doped into fullerene crystal. The change in positron lifetime made clear that some fraction of positrons annihilate in fullerene molecules while the others in interstitial sites among the molecules.