Structural Characterization of Unprecedented Al<sub>14</sub>O<sup>–</sup> and Al<sub>15</sub>O<sub>2</sub><sup>–</sup>: Photoelectron Spectroscopy and Density Functional Calculations

2013-04-04T00:00:00Z (GMT) by Tomomi Watanabe Tatsuya Tsukuda
New aluminum oxide clusters Al<sub>14</sub>O<sup>–</sup> and Al<sub>15</sub>O<sub>2</sub><sup>–</sup> were observed unprecedentedly in the gas-phase reaction of Al<sub><i>n</i></sub><sup>–</sup> and O<sub>2</sub>. Photoelectron spectroscopic measurements and density functional calculations indicated that Al<sub>14</sub>O<sup>–</sup> and Al<sub>15</sub>O<sub>2</sub><sup>–</sup> are composed of an icosahedral Al<sub>13</sub> moiety bonded by one and two OAl unit(s), respectively. The preferential formation of Al<sub>14</sub>O<sup>–</sup> and Al<sub>15</sub>O<sub>2</sub><sup>–</sup> is explained in terms of the high stability associated with the Al<sub>13</sub> moiety and efficient collisional trapping as intermediates of oxidative etching reactions.