对体系局部进行高精度量子化学计算的研究

用对大体系的局部区域进行高精度量子化学计算的新方法，对腈、酰胺、醚、醛、羧酸、硝基化合物、卤代物等不同类型的多种有机分子体系进行计算，得到电荷分布、键断裂能、电离势与电负性等方面的数据.为了比较，同时对上述体系进行整体的和模型体系的高精度计算.局部高精度计算与整体高精度计算的结果相当一致，优于模型体系的计算结果，进一步表明了局部高精度量子化学计算方法的可行性.

Study on High Accurate Quantum Chemical Calculations Carried Out in a Local Region of a System

The method proposed by us to carry out high accurate density functional calculations in a local region of a large system was applied t o the calculation of a series of diffe rent type of molecules and the data su ch as Mulliken charges,bond lengths,b ond dissociation energies,the firs t ionization potentials and electro nega-tivities were obtained.The high acc urate calculations for the same set o f molecules and the correspondent mo del molecules with a hydrogen atom repla cing the part of a molecule surroundi ng the local region were also carried out with the conventional method for comparison.It is found that the resu lts obtained by the local high accura te calculation are in good agreement wi th those obtained by the conventional high accurate calculation while th e calculated results for the model mol ecules show larger deviation.The re sults presented in this paper show fu rther that the local high accurate calcula tion method proposed by us is practic al and valuable.