Short and long bonds in liquid tellurium
Short and long bonds in liquid tellurium
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DOI：
10.1016/s0022-3093(99)00275-6
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发表时间：
1999-08
影响因子：
3.5
通讯作者：
Y. Kawakita;M. Yao;H. Endo
中科院分区：
文献类型：
--
作者：
Y. Kawakita;M. Yao;H. Endo
液态碲（Te）是金属，这是由相邻链分子之间的强相互作用引起的。随着温度从熔点（~ 450°C）降低到过冷状态（~ 250°C），液态Te经历了从金属到半导体的转变（M-S转变），伴随着体积膨胀。我们的过冷液体Te的EXAFS数据采用“模型无关”的方法仔细分析。结果表明，具有金属性质的液态Te的短链由短共价键（~ 2.80 Å）和长共价键（~ 2.95 Å）组成，长共价键在M-S跃迁中消失。在液体Te中加入碱也会发生上述的M-S转变。从链分子中电荷波动的角度解释了长共价键的存在与金属行为的关系。
Liquid tellurium (Te) is metallic, which is caused by the strong interaction between neighbouring chain-molecules. With decreasing temperature from the melting point (∼450°C) to a supercooled state (∼250°C), liquid Te undergoes a transition from a metal to a semiconductor (M–S transition) being accompanied by volume expansion. Our EXAFS data for supercooled liquid Te were carefully analyzed by adopting a `model-independent' method. It is found that the short chains in liquid Te with metallic nature are composed of short(∼2.80 Å) and long(∼2.95 Å) covalent bonds and that the long bonds vanish on the M–S transition. The M–S transition described above also occurs by the addition of an alkali to liquid Te. The relation of the existence of long covalent bond and the metallic behavior is explained in term of charge fluctuations in the chain molecule.