Drift tube ion mobility spectrometry (DTIMS) coupled with mass spectrometry was used to determine the collision cross-sections (^DTCCS) of polyoxometalate anions in helium and nitrogen. As the geometry of the ion, more than its mass, determines the collision cross-section with a given drift gas molecule, we found that both Lindqvist ions Mo₆O₁₉²⁻ and W₆O₁₉²⁻ had a ^DTCCS_He value of 103 ± 2 Ų, and both Keggin ions PMo₁₂O₄₀³⁻ and PW₁₂O₄₀³⁻ had a ^DTCCS_He value of 170 ± 2 Ų. Similarly, ion mobility experiments in N₂ led to ^DTCCS_N2 values of 223 ± 2 Ų and 339 ± 4 Ų for Lindqvist and Keggin anions, respectively. Using optimized structures and partial charges determined from density functional theory calculations, followed by CCS calculations via the trajectory method, we determined Lennard-Jones 6-12 potential parameters ε, σ of 5.60 meV, 3.50 Å and 3.75 meV, 4.40 Å for both Mo and W atoms interacting with He and N₂, respectively. These parameters reproduced the CCS of polyoxometalates within 2% accuracy.

中文翻译：

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来自 Lindqvist 和 Keggin 多金属氧酸盐阴离子碰撞截面的 He 和 N2 中 Mo 和 W 的 Lennard-Jones 相互作用参数

漂移管离子淌度谱 (DTIMS) 与质谱联用用于确定多金属氧酸盐阴离子在氦和氮中的碰撞截面 ( ^DT CCS)。由于离子的几何结构（大于其质量）决定了与给定漂移气体分子的碰撞截面，我们发现 Lindqvist 离子 Mo ₆ O ₁₉ ^2-和 W ₆ O ₁₉ ^2-都具有^DT CCS _He值为 103 ± 2 Å ²，并且 Keggin 离子 PMo ₁₂ O ₄₀ ^3-和 PW ₁₂ O ₄₀ ^3-都具有^DT CCS_He值为 170 ± 2 Å ²。_{同样，N 2}中的离子迁移率实验导致^{Lindqvist 和 Keggin 阴离子的DT} CCS _N2值分别为 223 ± 2 Å ²和 339 ± 4 Å ²。使用由密度泛函理论计算确定的优化结构和部分电荷，然后通过轨迹方法进行 CCS 计算，我们确定了 Lennard-Jones 6-12 电位参数ε， σ为 5.60 meV，3.50 Å 和 3.75 meV，4.40 Å和W原子分别与He和N ₂相互作用。这些参数以 2% 的准确度再现了多金属氧酸盐的 CCS。