ESR study of Gamma-ray irradiated synthetic calcium carbonates

✍ Scribed by C. Jacobs; P. De Canniére; R. Debuyst; F. Dejehet; D. Apers

• Book ID: 103922128
• Publisher: Elsevier Science
• Year: 1989
• Weight: 356 KB
• Volume: 40
• Category: Article
• ISSN: 0883-2889
• DOI: 10.1016/0883-2889(89)90055-5

✦ Synopsis

Nine commercial calcium carbonates, plus 3 calcium carbonates which have been synthesized in the laboratory and 2 natural ones, have been 7-ray irradiated at room temperature. From these 14 samples, 11 are pure calcite, 2 are pure aragonite and 1 is a mixture of calcite and aragonite. Important differences in their ESR spectra are observed. A preheating treatment (up to 600°C) was performed in order to standardize the ESR spectra. After a heating treatment at 600°C for 2 h, all the samples are in the calcite phase; 6 of them mainly exhibit, after ),-ray irradiation, a paramagnetic species with gll = 2,0024 and g± =2.0037 (COl-?). A k-value of ~0.I for two radiolytic species (one at 2.0052 and the other, anisotropic, at 2.0037 and 2.0024) of three commercial samples of calcite is obtained by means of ~t-particle irradiation with an 24tAm source. 1148 C. JAcoBs et al.

analyses were fulfilled on a Perkin-Elmer TGS 2 system 4 instrument.