Danten Y, Tassaing T, Besnard M
Laboratoire de Physico-Chimie Moléculaire (U.M.R C.N.R.S 5803), Université Bordeaux I, 351, Cours de la Libération, 33405 Talence, France.
J Phys Chem A. 2005 Apr 14;109(14):3250-6. doi: 10.1021/jp0503819.
In this paper, we have calculated using the ab initio method the IR vibrational spectra of complexes of CO2 formed with water (sp3 O-donating atom). Binding energies and structures of the CO2-H2O and water-(CO2)2 complexes have been determined at the second-order level of the Moller-Plesset perturbation theory (MP2) using Dunning's basis sets. The results are presented and critically discussed in terms of the nature of the water-CO2 interactions, electron donor acceptor (EDA) and weak O...H-O interactions. For water-(CO2)2 trimer, it is also shown that the contribution to the interaction energy of the irreducible three-bodies remains relatively negligible. We have analyzed the frequency shifts and the IR and Raman intensity variations under the complex formation. We have particularly emphasized the splitting of the 2 bending mode of CO2 and stretching modes of water, which have been revealed as the most pertinent probes to assess the nature of the forces involved in the different complexes. Finally, because water can play the role of Lewis base and acid as well, we found that weak O...H-O interactions can cooperate with EDA interactions in trimer, leading to very specific spectral signatures that are further discussed.
在本文中，我们使用从头算方法计算了二氧化碳与水（sp3氧供体原子）形成的配合物的红外振动光谱。利用邓宁基组，在莫勒-普莱塞微扰理论（MP2）的二阶水平上确定了CO2-H2O和水-(CO2)2配合物的结合能和结构。根据水与二氧化碳相互作用的性质、电子供体-受体（EDA）以及弱O...H-O相互作用，对结果进行了展示和批判性讨论。对于水-(CO2)2三聚体，还表明不可约三体对相互作用能的贡献仍然相对可以忽略不计。我们分析了配合物形成过程中的频率位移以及红外和拉曼强度变化。我们特别强调了CO2的2个弯曲模式和水的伸缩模式的分裂，这些已被证明是评估不同配合物中所涉及力的性质的最相关探针。最后，由于水既可以充当路易斯碱也可以充当路易斯酸，我们发现弱O...H-O相互作用可以在三聚体中与EDA相互作用协同作用，从而产生非常特殊的光谱特征，对此将进一步讨论。
