In this work, the photoelectron spectrum of adenine (AD) interacting with one and two bare and microhydrated Na⁺ (AD-Na⁺, Na⁺-AD-Na⁺, AD-[Na(H₂O)_n]⁺ and [Na(H₂O)_n]⁺-AD-[Na(H₂O)_n]⁺) have been calculated in two environments including the gas phase and water, separately. The symmetry adapted/cluster configuration interaction (SAC-CI) methodology was employed to calculate the first to fifth ionization energies (IEs) of AD. The photoelectron spectra of AD-Na⁺ structures showed a shift to higher binding energy, depending on the interaction site of Na⁺, compared to the spectrum of bare AD in gas phase while a slight shift to lower binding energy was observed for the spectrum of the most stable structure of AD-Na⁺ in water compared to bare AD in the same condition. In the presence of second Na⁺, the gas phase photoelectron spectrum of Na⁺-AD-Na⁺ shifted to higher binding energy compared to the spectrum of AD-Na⁺. This energy shift was nearly independent of the interaction site of second Na⁺ and decreased, considerably in the water environment. The microhydration of Na⁺ in the AD-Na⁺ and Na⁺-AD-Na⁺ structures in the gas phase, shifted their photoelectron spectra to lower binding energies compared to the spectra of corresponding unhydrated structures depending on the number of water molecules. A similar trend was also observed in water. The hydration of Na⁺ could decrease the ionization energy of AD-Na⁺ and Na⁺-AD-Na⁺ structures in water even lower than the ionization energies of bare AD in the same conditions. The main electronic configurations of the ionization bands of each structure were determined and their changing with the Na⁺ interaction site, number of Na⁺ and hydration of Na⁺ were explained. The kind and contribution of Lewis orbitals in the canonical molecular orbitals participating in ionization were determined for each structure.

在这项工作中，腺嘌呤（AD）与一个和两个裸露的微水合Na ⁺（AD-Na ⁺，Na ⁺ -AD-Na ⁺，AD- [Na（H ₂ O）_n ] ⁺和[ Na（H ₂ O）_n ] ⁺ -AD- [Na（H ₂ O）_n ] ⁺）是在包括气相和水在内的两个环境中分别计算的。采用对称适应/簇构型相互作用（SAC-CI）方法来计算AD的第一至第五电离能（IEs）。AD-Na ⁺的光电子能谱相比于气相中裸AD的光谱，结构显示出向更高的结合能转变，这取决于Na ⁺的相互作用部位，而对于最稳定的AD-Na的光谱，观察到向较低的结合能略有转变。与相同条件下裸露的AD相比，水中的⁺含量更高。在第二Na ⁺的存在下，与AD-Na ⁺的光谱相比，Na ⁺ -AD-Na ⁺的气相光电子光谱向更高的结合能转移。这种能量转移几乎独立于第二Na ⁺的相互作用部位，并且在水环境中明显降低。Na ⁺在AD-Na中的微水化与相应的未水合结构的光谱相比，气相中的⁺和Na ⁺ -AD-Na ⁺结构将其光电子能谱转移到较低的结合能，这取决于水分子的数量。在水中也观察到类似的趋势。在相同条件下，Na ⁺的水合可降低水中AD-Na ⁺和Na ⁺ -AD-Na ⁺结构的电离能，甚至低于裸露的AD的电离能。确定了每种结构的电离带的主要电子构型，并随Na ⁺相互作用位点，Na ⁺数量和Na的水合而变化。⁺被解释。对于每种结构，确定了参与电离的规范分子轨道中的Lewis轨道的种类和贡献。