HCCO自由基与水分子氢键复合物的从头算研究

Ab initio study of the structure,cooperativity,and vibrational properties in the hydrogen-bonded dimers and trimers of HCCO and water

在MP2/aug-cc-pvdz水平下,对二体氢键复合物H2O…HCCO（Ⅰ）和HCCO…H2O（Ⅱ）以及三体氢键复合物（H2O）2…HCCO（Ⅲ）,H2O…H2O…HCCO（Ⅳ）和H2O…HCCO…H2O（V）的几何和相互作用能进行了计算.轨道分析表明Ⅲ中HCCO中的H（1）,C（2）通过2个氢键与2个水分子形成了环状复合物,而Ⅳ只有C（2）与2个水分子形成了环状复合物,并且C（2）与其中1个水分子间只有静电作用而不形成氢键,Ⅴ则是HCCO中所有原子都参与形成大环复合物.通过多体分析MBAC方法,分析了3种三体复合物的多体结合能.其中所有的三体能都是负值,二体能在总相结合能中占85%90%,三体能占10%15%.在二体能中,水分子之间的结合能强于水分子与HCCO之间的结合能.Ⅴ中的三体能最高,说明大环的复合物最不稳定.

The structures and decompositions of the interaction energies of two dimers of H2O…HCCO（Ⅰ）,HCCO…H2O（Ⅱ）,and three trimers of（H2O）2…HCCO（Ⅲ）,H2O…H2O…HCCO（Ⅳ）,H2O…HCCO…H2O（Ⅴ） have been studied at the MP2/aug-cc-pvdz level.The orbital analysis shows that two H2O molecules with C or H/C atoms in HCCO possess a ring structure in complex III and IV,respectively.And complex V possesses a large ring structure.By using the MBAC method,all three-body energies are negative in three trimers.Two-body energy is 85～90% in total cooperative energy,while the three-body energy is 10～15%.The two-body energy between water molecules is higher than that between water and HCCO.The three-body energy in complex V is the highest,which indicates that the large ring is not stable.