Consiglio Nazionale delle Ricerche - Istituto dei Sistemi Complessi, via Madonna del Piano 10, I-50019 Sesto Fiorentino, Italy.
J Phys Chem A. 2012 Sep 6;116(35):8827-32. doi: 10.1021/jp303968p. Epub 2012 Aug 22.
We have measured the Raman spectrum of ammonia borane at low temperature (T = 15 K) and across the orthorhombic-to-tetragonal phase transition at T = 225 K. A comprehensive study of the low frequency lattice modes using Raman spectroscopy has been carried out. Data analysis has been complemented by a density functional theory calculation of which the results have been used for a detailed assignment of the Raman active modes. The analysis of the spectroscopic measurements taken across the phase transition seems to be consistent with the increasing orientational disorder of the molecular components and seems to be compatible with the equalization of the a and b lattice constants characteristic of the tetragonal phase.
我们已经在低温（T=15K）下测量了氨硼烷的拉曼光谱，并在 T=225K 下测量了正交相到四方相的相变。我们利用拉曼光谱对低频晶格模式进行了全面研究。数据分析补充了密度泛函理论计算，结果用于详细分配拉曼活性模式。对相变过程中光谱测量的分析似乎与分子成分的取向无序增加一致，并且似乎与四方相特征的 a 和 b 晶格常数相等化兼容。
