The experimental hydration energies of Mn²⁺(H₂O)_x complexes, where x = 4–9, are determined by threshold collision-induced dissociation (TCID) with Xe using a guided ion beam tandem mass spectrometer, coupled with an electrospray ionization (ESI) source. The ESI source naturally produces intense beams of the x = 7–9 complexes, but smaller complexes, x = 4–6, can be formed using an in-source fragmentation technique. For all systems, the dominant fragmentation processes observed are sequential loss of water ligands, but at x = 4 and 5, charge separation (CS) reactions are observed where formation of singularly charged species becomes competitive. Kinetic energy-dependent cross sections are obtained and analyzed to yield 0 K bond dissociation energies (BDEs) for the losses of one and two water ligands, which are then converted to 298 K binding enthalpies and Gibbs energies. Barrier heights for three different CS reactions are also determined. These thermodynamic results are compared with values obtained theoretically, with reasonable agreement being achieved. Theoretical geometry and single-point energy calculations are performed at B3LYP, B3P86, M06, and MP2(full) levels of theory.

Mn ²⁺ (H ₂ O) _x复合物的实验水合能，其中x  = 4–9，通过使用引导离子束串联质谱仪与 Xe 的阈值碰撞诱导解离 (TCID) 以及电喷雾电离来确定(ESI) 来源。ESI 源自然会产生x  = 7-9 复合物的强光束，但更小的复合物x  = 4-6 可以使用源内碎裂技术形成。对于所有系统，观察到的主要碎裂过程是水配体的连续损失，但在x = 4 和 5，观察到电荷分离 (CS) 反应，其中单电荷物质的形成变得有竞争力。获得并分析动能相关横截面以产生 0 K 键解离能 (BDE)，用于损失一个和两个水配体，然后将其转换为 298 K 结合焓和吉布斯能量。还确定了三种不同 CS 反应的势垒高度。将这些热力学结果与理论上获得的值进行比较，取得了合理的一致性。理论几何和单点能量计算在 B3LYP、B3P86、M06 和 MP2（完整）理论水平上进行。