Compact Non-Rock-Salt Structures in Sodium Fluoride Cluster Ions at Specific Sizes Revealed by Ion Mobility Mass Spectrometry

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• 作者：Keijiro Ohshimo ; Tohru Takahashi ; Ryoichi Moriyama ; Fuminori Misaizu
• 刊名：Journal of Physical Chemistry A
• 出版年：2014
• 出版时间：October 30, 2014
• 年：2014
• 卷：118
• 期：43
• 页码：9970-9975
• 全文大小：355K
• ISSN：1520-5215

文摘

Structures of small sodium fluoride cluster cations, Na_nF_n鈥?⁺, have been determined for n = 5鈥?3 by ion mobility mass spectrometry. In the mass spectrum of Na_nF_n鈥?⁺ cluster ions measured after collisions in the ion-drift cell, cuboid ions with near-regular hexahedron such as n = 14 (3 脳 3 脳 3), 23 (3 脳 3 脳 5), 38 (3 脳 5 脳 5), 63 (5 脳 5 脳 5), and 88 (5 脳 5 脳 7) were predominantly observed as magic numbers. By comparison of the collision cross sections obtained from the ion mobility measurements with theoretical ones, we have experimentally shown that the ions of n = 7 and 10 have stable non-rock-salt type structures in which one sodium atom is encapsulated into the sodium fluoride cuboid lattice. The collision cross sections of n = 12 and 13 are almost equal to that of the n = 14 cuboid. A similar feature was also observed in collision cross sections of n = 21 and 22, which are equal to that of the n = 23 cuboid. These features indicate that the cluster ions of n = 12, 13, 21, and 22 have near-cuboid structures with some surface defects.