Inelastic neutron scattering study of the ``rotator'' phase transition in n ‐nonadecane
Inelastic neutron scattering study of the ``rotator'' phase transition in n ‐nonadecane
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正十九烷中“旋转体”相变的非弹性中子散射研究
DOI：
10.1063/1.1679130
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发表时间：
1973
期刊：
影响因子：
--
通讯作者：
J. Barnes
中科院分区：
文献类型：
--
作者：
J. Barnes
本文提出了一个简单的正构烷烃绕长轴旋转跳跃扩散的运动学模型（环形无规行走模型）。在美国国家标准局反应堆费米斩波器飞行时间仪上获得的非弹性中子散射数据使用入射中子波长为2.47 A（Δ λ/λ = 3.8%）与模型的预测进行了比较。在十九烷中低于“临界”相变温度（295 °K）的数据显示，由于扩散运动，没有准弹性散射。在正十九烷的无序固相中采集的数据显示出与圆形随机游走模型一致的准弹性散射。模型参数值的估计值为3.5 psec。对于τ1和N ≥ 8，得到了
A simple kinematic model for rotational jump diffusion of a normal alkane about its long axis (circular random walk model) is developed. Inelastic neutron scattering data obtained on the Fermi chopper time‐of‐flight instrument at the National Bureau of Standards reactor using an incident neutron wavelength of 2.47 A (Δ λ/λ ≃ 3.8 %) are compared with the predictions of the model. Data taken below the temperature of the ``rotator'' phase transition in n ‐nonadecane (295 °K) show no quasielastic scattering due to diffusive motions. Data taken in n ‐nonadecane in its disordered solid phase show quasielastic scattering consistent with the circular random walk model. Estimates for values of the model parameters of 3.5 psec. for τ1 and N ≥ 8 are obtained.