HOME > プロフィール > ロク シンガプリゲ ロシャンタ クマーラ
Nanoparticles, Thin films, Amorphous, Synchrotron X-rays, X-ray diffraction, X-ray absorption fine structure spectroscopy, hard X-ray photoelectron spectroscopy , pair distribution function (PDF) , reverse Monte Carlo (RMC)
1). Characterization & computer simulation studies on transition metal nanoparticles for catalysts by high-energy X-ray diffraction coupled to pair distribution function (PDF) and reverse Monte Carlo (RMC) modelling method, extended X-ray absorption fine structure spectroscopy (EXAFS), X-ray absorption near edge structure (XANES) and hard X-ray photoelectron spectroscopy (HAXPES). 2). Synthesis, characterization & computer simulation studies of chalcogenide semiconductor glasses and melts by means of X-ray and Neutron Diffraction and EXAFS. 3). Characterization of studies on oxide thin films and amorphous thin films, by high-energy X-ray diffraction, EXAFS, anomalous X-ray scattering (AXS), and RMC method. 4). Synchrotron X-rays techniques; high resolution powder XRD, thin films XRD , high-energy XRD, small angle X-ray scattering (SAXS), AXS, EXAFS, XANES and HAXPES. 5). The correlation between functional physical properties and characteristics structure of condensed matters.
My current research focuses on characterization of nanomaterials by utilizing synchrotron X-rays. Nanotechnology, the creation of functional materials, device, and system through the control of nanoscale materials, has recently become one of most active research field. Particle with diameters in the range of 2 to 100 nm, called nanoparticles (NPs), have become a major interdisciplinary area of research during recent decades due to various applications including fuel-cell electrocatalysts and automobile exhaust gas catalysts. Because catalytic reactions occur at the surface, nanosized metal catalysts are typically used in catalysis to improve the catalytic efficiency, by increasing the surface-to-volume ratio. Recently, the Kitagawa group at Kyoto University has reported the structural identification of novel fcc-type Ru NPs and the size dependency of their more efficient catalytic activity than conventional hcp-type Ru NPs. However, the catalytic properties of NPs are strongly dependent on their atomic-scale structure, which is difficulty determined by conventional powder X-ray diffraction. In collaboration with Kitagawa group, I have previously developed a method to investigating three-dimensional atomic-scale structure of Ru nanoparticles by using HEXRD techniques coupled with pair distribution function (PDF) and reverse Monte Carlo (RMC) modelling method [Phys. Chem. Chem. Phys., 2016, 18, 30622-30629]. The RMC simulation of the atomic-scale structure of spherical particle without applying periodic boundary conditions allows the testing and refining of structure models based directly on diffraction data of spherical like nanoparticles with free surface and inhomogeneities in the atomic ordering.
- CHEN, Yanna, SAKATA, Osami, NANBA, Yusuke, LOKU SINGGAPPULIGE, Rosantha Kumara, Anli Yang, SONG, ChulHo, KOYAMA, Michihisa, Guangqin Li, Hirokazu Kobayashi, Hiroshi Kitagawa. Electronic Origin of Hydrogen Storage in MOF-covered Palladium Nanocubes Investigated by Synchrotron X-rays. COMMUNICATIONS CHEMISTRY. 1 (2018)
- Takuo Wakisaka, Kohei Kusada, Dongshuang Wu, Tomokazu Yamamoto, Takaaki Toriyama, Syo Matsumura, Hiroshi Akiba, Osamu Yamamuro, Kazutaka Ikeda, Toshiya Otomo, Natalia Palina, Yanna Chen, Loku S. R. Kumara, Chulho Song, Osami Sakata, Wei Xie, Michihisa Koyama, Yoshiki Kubota, Shogo Kawaguchi, Ryan L. Arevalo, Susan M. Aspera, Elvis F. Arguelles, Hiroshi Nakanishi, Hiroshi Kitagawa. Rational Synthesis for a Noble Metal Carbide. Journal of the American Chemical Society. 142  (2020) 1247-1253 10.1021/jacs.9b09219
- Ibrahima Gueye, Jaemyung Kim, L.S.R. Kumara, Anli Yang, Okkyun Seo, Yanna Chen, Chulho Song, Satoshi Hiroi, Kohei Kusada, Hirokazu Kobayashi, Hiroshi Kitagawa, Osami Sakata. Investigation of selective chemisorption of fcc and hcp Ru nanoparticles using X-ray photoelectron spectroscopy analysis. Journal of Catalysis. 380 (2019) 247-253 10.1016/j.jcat.2019.10.004
- L. S. R. Kumara, Osami Sakata, Shinji Kohara, Anli Yang, Chulho Song, Kohei Kusada, Hirokazu Kobayashi, Hiroshi Kitagawa. Structural studies of metal nanoparticles using high-energy x-ray diffraction. AIP Conference Proceedings. 2016
- LOKU SINGGAPPULIGE, Rosantha Kumara, YANG, Anli, SAKATA, Osami, Ryosuke Yamauchi, Munetaka Taguchi, Satoshi Ishimaru, Akifumi Matsuda, Mamoru Yoshimoto. LixNi1-xOのエピタキシャル薄膜の電子構造の研究. 2014年 第61回応用物理学会春季学術講演会. 2014
- LOKU SINGGAPPULIGE, Rosantha Kumara, SAKATA, Osami, SONG, ChulHo, KOHARA, Shinji, Kohei Kusada, Hirokazu Kobayashi, Hiroshi Kitagawa. Investigation of atomic-scale structure effects on the catalytic activity of metallic nanoparticles by synchrotron X-ray based PDF analysis and RMC modelling methods. The 30th Fall Meeting of The Ceramic Society of Japan. 2017
- KATSUYA, Yoshio, TANAKA, Masahiko, UEDA, Shigenori, YAMASHITA, Yoshiyuki, SHIMADA Yoshitomo, ISHIMARU Satoshi, YANG, Anli, LOKU SINGGAPPULIGE, Rosantha Kumara, SAKATA, Osami. 物質・材料研究機構ビームラインBL15XUの現状. SPring-8シンポジウム2013. 2013
The Japan Society of Applied Physics , Crystallographic Society of Japan , International X-ray Absorption Society , European Neutron Scattering Association