Temperature evolution between 50 K and 320 K of the thermal expansion tensor of gypsum derived from neutron powder diffraction data
Temperature evolution between 50 K and 320 K of the thermal expansion tensor of gypsum derived from neutron powder diffraction data
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根据中子粉末衍射数据得出的石膏热膨胀张量在 50 K 和 320 K 之间的温度演变
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发表时间：
1999
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影响因子：
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通讯作者：
P. Schofield
中科院分区：
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作者：
K. Knight;I. Stretton;P. Schofield
摘要 从 4.2 K 到 320 K 之间收集的中子粉末衍射数据的 Rietveld 分析中提取的晶胞参数已用于计算 50 ≤ T ≤ 320 K 时石膏热膨胀张量的温度演化。在 300 K 时，主轴的大小为 α11 = 1.2(6) × 10−6 K−1，α22 = 36.82(1) × 10−6 K−1且 α33 = 25.1(5) × 10−6 K−1。最大轴 α22 与 b 平行，并且使用无线电工程师协会 (IRE) 约定作为张量正交基，轴 α11 和 α33 的方向分别等于 (−0.979, 0, 0.201) 和 (0.201, 0, 0.979)。热膨胀张量的取向和温度相关行为与 I2/a 设置中的晶体结构有关。
Abstract The unit cell parameters, extracted from Rietveld analysis of neutron powder diffraction data collected between 4.2 K and 320 K, have been used to calculate the temperature evolution of the thermal expansion tensor for gypsum for 50 ≤ T ≤ 320 K. At 300 K the magnitudes of the principal axes are α11 = 1.2(6) × 10−6 K−1, α22 = 36.82(1) × 10−6 K−1 and α33 = 25.1(5) × 10−6 K−1. The maximum axis, α22, is parallel to b, and using Institution of Radio Engineers (IRE) convention for the tensor orthonormal basis, the axes α11 and α33 have directions equal to (−0.979, 0, 0.201) and (0.201, 0, 0.979) respectively. The orientation and temperature dependent behaviour of the thermal expansion tensor is related to the crystal structure in the I2/a setting.