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4.3

Diatoms and the nanotechnology

K. Tk´si, R.J. Bereczky, Gy. Lakatos a) and C. Cserh´ti b) o e a During the last decade studies of interactions between highly charged ions (HCI) and solid surfaces are at the center of interest which is partly stimulated by potential future technical application such as nanofabrication. The investigation of the interactions of highly charged ions with internal surfaces recently become available due to the advances in the fabrication of micro- and nanocapillaries. These target materials offer the opportunity to observe "hollow atom" formation in free space. Hollow atoms are an exotic form of matter where the atomic charge cloud resides in shells with large diameters while the core is virtually empty. In the past there has been an increasing amount of indirect evidence for the existence of this atomic state. Microcapillary transmission promises to provide direct evidence for the hollow atom formation for the first time. Our earlier theoretical descriptions rely on metallic microcapillaries which have proven to be quite successful in comparison with experimental data [1]. However, since very detailed measurements have recently become available for insulator nanocapillaries, critical and precise tests of theory are only now being possible [2]. We note, that the theoretical description of the interaction between the HCI and insulator nanocapillaries is far from being well understood. One of the key point of the experimental investigations is the preparation of the nanocapillaries. In this work we propose an alternative way to prepare insulator nanocapillaries. We take an advantage of the nature that during the evolution the cylindrical shape nanostructure was developed as a truss of diatoms [3]. The truss of the diatoms contains roughly 99 % SiO2 and in some cases of diatoms it form almost ideal cylindrical shape. As an example Fig. 1 shows the scanning electron micrograph of the diatom. The size of the holes in the truss are in the nanometer range (see Fig. 1a). On the basis of these properties the diatoms can be ideal candidate for insulator nanocapillaries in our forthcoming experiments.

Figure 1. Scanning electron micrograph of the diatom.

Acknowledgements The work was supported by the grant "Bolyai" from the Hungarian Academy of Science, and T´T Grant No. A-15/04. e

a) Ecological Institute, Univ. of Debrecen b) Dept. of Solid State Physics, Univ. of Debrecen [1] K. Tk´si, L. Wirtz, C. Lemell, and J. Burgd¨rfer, o e o Phys. Rev. A 64 (2001) 042902. [2] N. Stolterfoht, et al., Phys. Rev. Lett. 88 (2002) 133201. [3] Gy. Lakatos, et al., Proceedings of the 10th International Svedala Symposium on Ecological Design, Sept. 11-13 (1992), p155.

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