Polysulfide anions play crucial roles in the liquid phase, but they are difficult to describe in theoretical calculations. We have investigated diffuse functions dependent total energy, bond length, and molecular orbitals for disulfide dianion (S₂^2-) in water using conventional ab initio unrestricted Hartree-Fock method (UHF/6-311G+(d)) with a polarizable continuum model (PCM, ε = 78.39) by changing ς value of diffuse functions. S₂^2- in water turns out to be more stable than S₂ and S₂^-, though it is too unstable to exist in vacuum so that the excess electrons will auto-detach. The optimal ς value that gives a local minimum of total energy for S₂^2- in water is found to be 0.12. These new findings will contribute toward using more appropriate diffuse functions for other polysulfide anions as well.

多硫化物阴离子在液相中起着至关重要的作用，但是在理论计算中很难描述。我们已经使用常规的从头开始的无限制Hartree-Fock方法（UHF / 6-311G +（d））和可极化连续体模型研究了扩散函数依赖于总能量，键长和水中二硫键二价键（S ₂ ^2-）的分子轨道的扩散函数（PCM，ε= 78.39），方法是更改​​漫反射函数的ς值。小号₂ ^2-水中原来是除S更稳定₂和S ₂ ^- ，虽然它太不稳定在真空中存在，以使过量的电子会自动分离。S ₂ ^2-给出局部最小总能量的最优ς值在水中的含量为0.12。这些新发现还将有助于对其他多硫化物阴离子使用更合适的扩散功能。