中文摘要：

利用量子化学计算方法,在HF/6-31＋G^＊水平下对硝酸锂溶液中可能存在的离子缔合物种,以及当浓度升高时溶液中发生的离子缔合过程进行了研究.硝酸根与水合锂离子可形成溶剂共享离子对、接触离子对、三离子及多离子团簇等离子缔合物种,在所有的缔合物种中,锂离子大都以形成四配位四面体结构为主,只有少数情况下存在能量较高的五配位结构.以上3种水合离子缔合物种中的v1（NO3^-）频率与水合硝酸根中的参比值相比,分别发生1.4,-6.9以及大于2.8 cm^-1的蓝移,考虑到实验光谱中v1（NO3^-）带是持续蓝移的.推测的硝酸锂溶液在浓度升高时发生离子缔合的过程可简略表示为＂自由水合离子→溶剂共享型离子对→阳-阴-阳型三离子团簇→链状多离子团簇→网状多离子团簇→晶体＂.这个过程与在硝酸镁和硝酸钠中的缔合过程是相似的.

英文摘要：

In the present article,the associated species and process in the LiNO3 solution is investigated at the HF/6-31＋G^＊ level.The NO3-ions binding with hydrated Li＋ ions can form solvent-shared ion pairing,contact ion pairing and multiple（including triple） ion clusters.Most of the Li^＋ ions have tetracoordinated structures while a few of them have pentacoordinate structures.The v1（NO3^-） frequencies in the species above are 1.4,-6.9 and 2.8 cm^-1 larger than the reference value in hydrated NO3^-.Considering the continued blue shift in the Raman spectrum in experiment,the associated process in the LiNO3 solution can be expressed as ＂free hydrated ion →solvent-shared ion pairing →solvent-shared cation-anion-cation triple ion cluster →catenulate multiple ion cluster →reticular multiple ion cluster →crystal＂.The process is analogous with those in the Mg（NO3）2 and NaNO3 systems.