咪唑-1-乙酸:中性分子及两性离子的自洽反应场研究

Imidazol1ylacetic Acid: SCRF Studies on its Neutral Form \=and Zwitterion

对咪唑－１－乙酸中性分子和两性离子分别在气相及水溶液中（采用ＳＣＲＦ模型）进行了从头算，探讨了溶剂和基组对体系几何结构和相对稳定性的影响。结果表明，气相中咪唑－１－乙酸主要以中性分子形式出现。

Ab initio calculations have been performed for both the neutral form and zwitterion of imidazol1ylacetic acid in the gas phase and in aqueous solution(using SCRF model). The influences of solvent and basis sets on the geometry and relative stability of the species are discussed.The results indicate that the zwitterionic form of the title compound have stronger solvent effects than the neutral form. In the gas phase, the neutral form is predicted to be strongly favored, but in aqueous solution, imidazol1ylacetic acid exists considerably in the zwitterionic form because of the polarization effects of solvent, which are in good agreement with experiment.\;