1. Toward the theoretically observable limit of electron density distribution by single-crystal synchrotron X-ray diffraction: The case of orbitally ordered Ti-3d^1 in YTiO_3
- Author
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Sakakura, Terutoshi, Ishikawa, Yoshihisa, Kishimoto, Shunji, Takenaka, Yasuyuki, Tanaka, Kiyoaki, Miyasaka, Shigeki, Tokura, Yoshinori, Noda, Yukio, Ishizawa, Nobuo, Sagayama, Hajime, Yamamoto, Hajime, and Kimura, Hiroyuki
- Subjects
Condensed Matter - Materials Science - Abstract
The theoretically observable limit of electron density distribution by single-crystal X-ray diffraction is discussed. When F_{orb} and {\delta}F are defined as, respectively, the partial structure factor for an orbital and the deviation of the observed F from the true F, the accuracy of electron density attributable to F_{orb} is chiefly determined by the number of reflections satisfying the condition F_{orb}/F > {\delta}F/F. Since F_{orb}/F, which is generally small for crystals with large F(0,0,0), is constant under a given set of experimental conditions, {\delta}F/F must be reduced to increase the number of reflections satisfying F_{orb}/F > {\delta}F/F. The present paper demonstrates how to reduce {\delta}F mathematically and experimentally, and the following topics are covered: the Poisson statistics, accumulation of errors in the data collection and reduction procedure, multiple diffraction, conversion error from F^2 to F in refinement programs, which is unavoidable when the input quantities have different dimension from F, weighting of reflections, and tips. For demonstration, observation of the electron density of the Ti-3d^1 orbital in YTiO_3 by synchrotron single-crystal X-ray diffraction is presented., Comment: 68 pages, 20 figures
- Published
- 2023