红绿柱石的吸收光谱

OPTICAL ABSORPTION OF RED BERYL

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＋。

What has caused the color of red beryl,Mn 2+ or Mn 3+ ? 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.