TL in green tourmaline: Study of the centers responsible for the TL emission by EPR analysis

Author(s)

Cano, Nilo F. ^[1] ; Rao, T. K. Gundu ^[2] ; Ayala-Arenas, Jorge S. ^[3] ; Gonzales-Lorenzo, Carlos D. ^[2] ; Oliveira, Leticia M. ^[4] ; Watanabe, Shigueo ^[2]

Affiliation

^[1] Univ Fed Sao Paulo, Inst Mar, Rua Doutor Carvalho Mendonca 144, BR-11070100 Santos, SP - Brazil

^[2] Univ Sao Paulo, Inst Fis, Rua Matao 187, BR-05508090 Sao Paulo, SP - Brazil

^[3] UNSA, Fac Ciencias Nat & Formales, Escuela Profes Fis, Av Independencia S-N, Arequipa - Peru

^[4] IPEN, CNEN SP, Av Prof Lineu Prestes, 2242, Cidade Univ, BR-05508000 Sao Paulo, SP - Brazil

• Document type: Journal article
• Source: Journal of Luminescence; v. 205, p. 324-328, JAN 2019.
• Web of Science Citations: 3

Abstract

Electron paramagnetic resonance (EPR) studies have been carried out to identify the defect centers responsible for the thermoluminescence (TL) peaks in the mineral tourmaline. The mineral exhibits three TL peaks approximately at 170, 250 and 310 degrees C. The EPR spectrum of the green tourmaline sample pre-heated to 500 degrees C presented a large signal around g = 4.3 due to Fe3+ ion. Room temperature EPR spectrum of irradiated green tourmaline shows the formation of two defect centers in the region of g = 2.0. One of the centers (center II) with a g factor equal to 1.96 is identified as an F+-center and is related to the observed high temperature 250 and 310 degrees C TL peaks. Center I exhibiting a doublet is due to hydrogen atoms (H-0), stable in the crystal lattice at room temperature and this center correlates with the TL peak at 170 degrees C of the green tourmaline. An optical absorption measurement also was carried out. Bands at around 430, 730 and 1100 nm have been observed. (AU)

• FAPESP's process: 14/03085-0 - Quaternary geochronology of Southeastern and Southern coast of Brazil
• Grantee: Shigueo Watanabe
• Support Opportunities: Research Projects - Thematic Grants