Khiri Dorra, Vandeputte Romain, Taamalli Sonia, Cantrel Laurent, Louis Florent
PhysicoChimie des Processus de Combustion et de l'Atmosphère (PC2A) UMR CNRS 8522, University of Lille, 59000, Lille, France.
Laboratoire cinétique chimique, combustion et réactivité (C3R), Laboratoire de Recherche Commun IRSN-CNRS-Lille, Cadarache, 13115, St Paul Lez Durance, France.
J Mol Model. 2019 Jul 1;25(7):207. doi: 10.1007/s00894-019-4094-4.
The structures and thermodynamic properties of microhydrates of caesium metaborate (CsBO) of nuclear safety interest are reported in this work. CsBO + n HO (n = 1-4) molecular complexes were identified on the potential energy surface. The structures were optimized using the ωB97XD DFT method and the aug-cc-pVTZ basis set. Single-point energies were calculated at the CCSD(T)-F12a/awCVTZ and the ωB97XD/aug-cc-pVQZ levels of theory. The standard reaction enthalpies and the standard Gibbs free reaction energies were reported for all molecular complexes. The temperature dependence of ΔG°(T) was evaluated for all studied structures over the temperature range 300-2000 K. Total hydration reactions were investigated. The results showed that the mono-hydrated form of CsBO exists only at temperatures lower than 720 K under standard conditions. The influence on the thermodynamic properties of the number of water molecules in the clusters was described, with successive dehydration from 720 to 480 K. In nuclear severe accident conditions, gaseous CsBO will remain unhydrated in the reactor coolant system.
本文报道了具有核安全意义的偏硼酸铯（CsBO）微水合物的结构和热力学性质。在势能面上识别出了CsBO + nH₂O（n = 1 - 4）分子复合物。使用ωB97XD密度泛函理论方法和aug-cc-pVTZ基组对结构进行了优化。在CCSD(T)-F12a/awCVTZ和ωB97XD/aug-cc-pVQZ理论水平上计算了单点能量。报道了所有分子复合物的标准反应焓和标准吉布斯自由反应能。评估了所有研究结构在300 - 2000 K温度范围内ΔG°(T)的温度依赖性。研究了总水合反应。结果表明，在标准条件下，CsBO的一水合物形式仅在低于720 K的温度下存在。描述了团簇中水分子数量对热力学性质的影响，在720至480 K范围内会发生连续脱水。在核严重事故条件下，气态CsBO在反应堆冷却剂系统中将保持未水合状态。
