锗原子量的新测定(英文)

Redetermination of the Atomic Weight of Germanium

摘要: 用两种高富集锗同位素配制的标准混合溶液系列 ,以标定一台 MAT-2 62热电离质谱仪 ,求得 4个同位素丰度比的校准因数 ,从而测得 5种天然锗样品的 4个同位素丰度比的真值。由此计算天然锗 5种同位素的丰度值如下 :2 0 .37± 0 .0 5　　原子 %70 Ge2 7.38± 0 .0 4　　原子 %72 Ge7.76± 0 .0 5　　原子 %73 Ge36.66± 0 .0 5　　原子 %74 Ge7.83± 0 .0 5　　原子 %76Ge再各乘以已知的原子质量 ,得出锗原子量的新值为 :Ar( Ge) =72 .639± 0 .0 0 4这些精确数值的置信度为 95%。优于文献上所有已知的相应值。

Abstract: A MAT 262 thermal ionization mass spectrometer was calibrated by using the gravimetric synthetic mixtures of highly enriched germanium isotopes in the form of oxides with known chemical purity.Measurements on natural germanium samples yielded an absolute isotopic composition of 20 37(5) at.% 70 Ge,27 38(4) at.% 72 Ge,7 76(5) at.% 73 Ge,36 66(5)at.% 74 Ge and 7 83(5)at.% 76 Ge,and the atomic weight of germanium as 72 639(4) both with an uncertainty given on the basis of 95% confidence limit.