1987 Fiscal Year Final Research Report Summary
Crystallographic study of metal clusters and one-dimensional atomic strings under restricted geometry conditions
| Project/Area Number |
61540254
|
|---|
| Research Category |
Grant-in-Aid for General Scientific Research (C)
|
| Allocation Type | Single-year Grants |
|---|
| Research Field |
物性一般（含極低温･固体物性に対する理論）
|
|---|
| Research Institution | TOHOKU UNIVERSITY |
|---|
Principal Investigator |
TERASAKI Osamu Department of Physies, Tohoku University, 理学部, 助手 (30004401)
|
|---|
| Project Period (FY) |
1986 – 1987
|
| Keywords | Restricted Geometry / Zeolites / High Resolution Electron Microscopic Image / Low-Dimensional materials / メタルクラスター |
|---|
| Research Abstract |
Zeolites are aluminosilicates with open structures in which channels and cavities are the size of small molecules, and therefore it is well appreciated that zeolites can act as adsorbents and catalysts. Furthermore they were recently used as dielectric containers giving a restricted geometry condition to the guests. This may be a novel method of producing well-defined low-dimensional materials. Many synthetic zeolites are now available and we can choose proper zeolite from its size and dimensionarity of the space. Direct obscrvation of the gucsts by HREM, showing their locations relative to the frameworks and the sizes of gucsts, is of considerable interest. No such observation has been reported so far. The aims of the present study are to incorpolate materials into the channcls or cavities of zeolites for making new low-dimensional solids and to characterize them crystallographically by observing HREM images. Se (coordination number 2) has relatively invariant values for bond angle, d
… More
ihedral angle and bond length, thus So atoms are expected to form clusters(rings) or one-dimensional chains depending where they are accommodated and it is easy to load it from the vapour phase. Three zeolites, i.e. MOR, L and Y, were chosen for their particular geometrical features. Zeolite L and MOR have one-dimengional channels running along the e axis, and their aperture sizes are 7.1 A and 6.7x7.0 A, respectively. Y has intersecting channels paral-lel to the <110> and at the same time has big spherical cavities 13.6 A in diameter which are connected to cach other through apertures of 7.4 A. Seatoms were clearly observed as black contrast in HREM images, which were well simulated by assuming that they were accommodated in the form of one(MOR) and plural (L) chains in the main channcls, and of clusters in the cavities(Y).
These results are also consistent with the regults of diffuse refleetion spectra from incorpolated Se, which is a joint work with Dr. Y. Nozue and Prof.T. Goto(Dept. of Phys., Tohoku Univ.). Less
|
Research Products
(6 results)
