Nguyen Huu Tho, Cuong Ngo Tuan, Lan Ngo Thi, Tung Nguyen Thanh, Nguyen Minh Tho, Tam Nguyen Minh
Faculty of Natural Sciences Education, Sai Gon University 273 An Duong Vuong Street Ho Chi Minh City Vietnam.
Center for Computational Science, Faculty of Chemistry, Hanoi National University of Education Hanoi Vietnam.
RSC Adv. 2022 May 4;12(21):13487-13499. doi: 10.1039/d1ra08527a. eCollection 2022 Apr 28.
A theoretical study of geometric and electronic structures, stability and magnetic properties of both neutral and anionic GeM clusters with M being a first-row 3d transition metal atom, is performed using quantum chemical approaches. Both the isoelectronic GeSc anion and neutral GeTi that have a perfect Frank-Kasper tetrahedral shape and an electron shell filled with 68 valence electrons, emerge as magic clusters with an enhanced thermodynamic stability. The latter can be rationalized by the simple Jellium model. Geometric distortions from the Frank-Kasper tetrahedron of GeM having more or less than 68 valence electrons can be understood by a Jahn-Teller effect. Remarkably, DFT calculations reveal that both neutral GeSc and GeCu can be considered as superhalogens as their electron affinities (≥3.6 eV) exceed the value of the halogen atoms and even that of icosahedral Al. A detailed view of the magnetic behavior of GeM clusters shows that the magnetic moments of the atomic metals remain large even when they are quenched upon doping. When M goes from Sc to Zn, the total spin magnetic moment of GeM increases steadily and reaches the maximum value of 3 with M = Mn before decreasing towards the end of the first-row 3d block metals. Furthermore, the IR spectra of some tetrahedral GeM are also predicted.
采用量子化学方法对中性和阴离子型GeM团簇（其中M为第一行3d过渡金属原子）的几何和电子结构、稳定性及磁性进行了理论研究。具有完美Frank-Kasper四面体形状且价电子壳层填充有68个价电子的等电子体GeSc阴离子和中性GeTi，均作为具有增强热力学稳定性的幻数团簇出现。后者可以通过简单的金属球模型进行合理解释。具有多于或少于68个价电子的GeM团簇相对于Frank-Kasper四面体的几何畸变可以通过Jahn-Teller效应来理解。值得注意的是，密度泛函理论（DFT）计算表明，中性的GeSc和GeCu均可被视为超卤素，因为它们的电子亲和能（≥3.6 eV）超过了卤原子甚至二十面体Al的电子亲和能。对GeM团簇磁性行为的详细研究表明，即使原子金属在掺杂时被猝灭，其磁矩仍然很大。当M从Sc变化到Zn时，GeM的总自旋磁矩稳步增加，在M = Mn时达到最大值3，然后在第一行3d区金属接近末尾时减小。此外，还预测了一些四面体GeM的红外光谱。
