红绿柱石的吸收光谱
来源期刊：中南大学学报(自然科学版)1999年第1期
论文作者：李湘祁 戴塔根 袁奎荣
文章页码：1 - 3
关键词：红绿柱石;锰;偏振吸收光谱;顺磁共振谱
Key words：red beryl; manganese; polarized absorption spectroscopy; EPR spectroscopy
摘 要：应用电子顺磁共振谱和偏振吸收光谱对 产于美国犹他州的红绿柱石的颜色成因进行了研究,结果表明,绿柱石的深红色与Mn3＋,Fe3＋有关.顺磁共振谱中只出现3根Fe3＋线,没有Mn2＋的 超精细结构线,表明Mn不是以Mn2＋的形式存在.偏振吸收谱图中出现490,530nM(垂直C轴)和560nM(平行C轴)宽吸收带,前两者归因于 Mn3＋的自旋允许跃迁,后者与交换耦合离子对Mn3＋→Fe3＋相互作用有关.Mn3＋,Fe3＋等高价态离子的存在反映了红绿柱石形成于氧化环境 .
Abstract: What has caused the color of red beryl,Mn2+ or Mn3+ ? The question is still controversial.Using electron paramagnetic resonance and optical absorption spectroscopy,the present study suggests that manganese in the +3 valence state is responsible for the deep red color of red beryl from Wah Wah Mountains,Utah.Three Fe 3+ lines are obtained in the EPR spectrum, but there is no “hyperfine splitting” due to the Mn 2+ ion observerved, indicating that manganese exists in the +3 valence state.The color of red beryl is caused by several absorption bands at 490,530 nm(⊥ C axis) and 560 nm(∥ C axis).The first two bands are due to the crystal field transitions of Mn 2+ and the last band is induced by Mn 3+ →Fe 3+ charge transfer.The high valence state of manganese and iron ion indicates that red beryl is formed in oxidization environment.
