Thermally excited multiplet states in flame coal

✍ Scribed by A.B Więckowski; B Pilawa; W Wojtowicz; G.P Słowik; H Wachowska

• Publisher: Elsevier Science
• Year: 2001
• Tongue: English
• Weight: 108 KB
• Volume: 80
• Category: Article
• ISSN: 0016-2361
• DOI: 10.1016/s0016-2361(00)00115-0

✦ Synopsis

Paramagnetic centres of Polish ¯ame coal with a carbon content of 70.8 wt% were studied by electron paramagnetic spectroscopy at Xband (9.3 GHz). The in¯uence of the measuring temperature on its two-component EPR spectrum was analysed. The measurements of line intensity and linewidth were carried out in the temperature range 100±300 K. It was found that the broad Lorentz line present in the EPR spectrum of the studied coal is responsible for temperature dependence of integral intensity which does not ful®l the Curie law. This proves the existence of thermally excited multiplet states in ¯ame coal. Paramagnetic centres related to the narrow Lorentz line in ¯ame coal obey the Curie law.