Advances in X-Ray Chemical Analysis, Japan, 45 (2014) ISSN 0911-7806 NaCl Color Center in NaCl Takuya TSUJI, Hiroyuki IWASAKI and Jun KAWAI
NaCl Color Center in NaCl Takuya TSUJI, Hiroyuki IWASAKI and Jun KAWAI Division of Engineering Science, Faculty of Engineering, Kyoto University Sakyo-ku, Kyoto 606-8501, Japan Department of Materials Science and Engineering, Kyoto University Sakyo-ku, Kyoto 606-8501, Japan (Received 14 January 2014, Revised 6 February 2014, Accepted 7 February 2014) X-ray irradiation can produce color centers in alkali halide. Each compound irradiated with X-rays exhibits its own characteristic color. The color of crystals of NaCl changed to orange after X-ray irradiation at room temperature. It was still orange in a dark room, but the color changed to black after exposure to white fluorescent lamp. In addition, the color of NaCl changes to pale purple when irradiated with 405 nm laser after X-ray irradiation and to light brown when irradiated with 532 nm laser after X-ray irradiation. The color of the powder NaCl of 75 µm particle size became whiter after exposure to X-rays than that of 700 µm particle size. The single crystal NaCl turned orange after X-ray irradiation, but the color was returned to transparent after exposure to white fluorescent lamp. The NaCl of low purity (cooking salt) left under white fluorescent light after X-ray irradiation exhibited bluish color and violet. [Key words] Color center, NaCl, Sodium chloride, X-ray irradiation, Laser irradiation, White fluorescent lamp irradiation X X NaCl X X X NaCl 1 X NaCl NaCl X NaCl X X X 606-8501 606-8501 45 233 Adv. X-Ray. Chem. Anal., Japan 45, pp.233-240 (2014)
1. 1896 Goldstein 1 Goldstein 2 1965 Fritz 3 X de Boer 4 F 1937 F 5 X 6 F 7 NaCl NaCl X 2 X 8 NaCl 9 1900 NaCl X NaCl NaCl X X X NaCl 2. NaCl 99.5% NaCl X XFRA-190 X X Rh 30 kv 25 ma 20 X X NaCl NaCl 700 µm X 1 22 W 30 cm 1 1 234 45
Table 1 Wavelength and intensity of the laser. Manufacturer Class Wavelength (nm) Intensity (mw) Red laser KOKUYO 2 650 1 Green laser KOKUYO 2 532 1 Violet laser Ankaka.com unknown 405 30 Table 1 NaCl 5 SEM Fig.1 SEM 10 700 µm 75 µm NaCl 45 mm 36 mm NaCl 50 g 10 /min 801 10 1 /min Fig.1 SEM image of (a) NaCl (The average particle size was 700 µm.), (b) NaCl ground in a mortar (The average particle diameter was 75 µm.). Fig.2 SEM image of (a) NaCl ground in a mortar (The average particle diameter was 75 µm.), (b) Solar salt ground in a mortar (The average particle diameter was 98 µm.). 45 235
5 /min NaCl 5 3 SEM Fig.2 SEM 98 µm 73 µm X 20 22 W 1 X 1 X 20 1 3. 3.1 X Fig.3 Fig.3a X X Fig.3b X Fig.3c Fig.3d X X 405 nm Fig.3f 532 nm Fig.3g 405 nm Fig.3e Fig.3 Photos of (a) NaCl, (b) NaCl irradiated with X-rays, (c) NaCl kept in the dark after exposure to X-rays, (d) NaCl exposed to room light after exposure to X-rays, (e)nacl irradiated with 650 nm lazer after exposure to X-rays, (f) NaCl irradiated with 532 nm lazer after exposure to X-rays, (g) NaCl irradiated with 405 nm lazer after exposure to X-rays. 236 45
3.2 700 µm Fig.4 75 µm Fig.5 Fig.6 700 µm X Fig.4a 1 Fig.4b X Fig.4c Fig.4d 75 µm X Fig.5a 1 Fig.5b X X Fig.5c 405 nm Fig.5d) 75 µm 700 µm Fig.7 700 µm X Fig.4a Fig.4 Photos of NaCl (The average particle diameter was 700 µm.) (a) irradiated with X-rays, (b) exposed to room light after exposure to X-rays, (c) irradiated with X-rays to (b), (d) irradiated with 405 nm lazer to (b). Fig.5 Photos of NaCl (The average particle diameter was 75 µm.) (a) irradiated with X-rays, (b) exposed to room light after exposure to X-rays, (c) irradiated with X-rays to (b), (d) irradiated with 405 nm lazer to (b). Fig.6 Photos of NaCl (single crystal) (a) irradiated with X-rays, (b) exposed to room light after exposure to X- rays, (c) irradiated with X-rays to (b), (d) irradiated with 405 nm lazer to (b). 45 237
Fig.4b X Fig.5 X X Fig.6a Fig.6b X Fig.6c Fig.6d X 700 µm 75 µm 1 Fig.7 Photos of NaCl (a) ground in a mortar after exposure to X-ray, (b) ground in a mortar after X-ray irradiation and exposure to room light. 3.3 Fig.8 X Fig.8 Photos of solar salt (The average particle diameter was 98 µm.) (a) irradiated with X-rays, (b) exposed to room light after exposure to X-rays, (c) irradiated with X-rays to (b), (d) irradiated with 405 nm lazer to (b). Fig.9 Photos of Margarita salt (The average particle diameter was 73 µm.) (a) irradiated with X-rays, (b) exposed to room light after exposure to X-rays, (c) irradiated with X-rays to (b), (d) irradiated with 405 nm lazer to (b). 238 45
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