Seeburrun Neelum, Archibong Edet F, Ramasami Ponnadurai
Computational Chemistry Group, Department of Chemistry, Faculty of Science, University of Mauritius, Réduit, 80837, Moka, Mauritius.
J Mol Model. 2015 Mar;21(3):42. doi: 10.1007/s00894-014-2555-3. Epub 2015 Feb 13.
We present a systematic theoretical study on mono and digallium selenide clusters, Ga(m)Se(n) (m = 1, 2 and n = 1-4), along with their negatively and positively charged counterparts. Different theoretical methods, namely density functional theory (DFT), second-order Møller-Plesset perturbation theory (MP2) and coupled cluster singles and doubles, including non-iterative triples [CCSD(T)], were employed in conjunction with the 6-311+G(2df) basis set. The lowest-energy configurations of gallium selenides prefer to be planar, with the exception of cationic GaSe4 and Ga2Se4. The adiabatic electron affinities (AEA) of Ga(m)Se(n) (m = 1, 2 and n = 1-4) clusters range from 1.07 to 3.78 eV, and their adiabatic ionization potentials (AIP) vary from 7.57 to 8.76 eV using the CCSD(T)//B3LYP level of theory. It was found that the AEAs of gallium selenides do not depend solely on the electrophilicity of the clusters but also on their electronic structures. No significant trend was observed in the AIP values and HOMO-LUMO (H-L) gaps with increase in cluster size of the mono and digallium selenide series. Among the dissociation channels, the decomposition of GaSe4 → GaSe2 + Se2 was found to be thermodynamically most favored. Furthermore, the AEAs of GaSe2, GaSe3, GaSe4 and Ga2Se4 were found to exceed that of the chlorine atom and are therefore termed as 'superhalogens'. Finally, the AEAs of the Ga2X(n) (X = O-Se; n = 2-4) series were found to be almost similar.
我们对单镓硒化物和双镓硒化物团簇Ga(m)Se(n)（m = 1、2且n = 1 - 4）及其带负电荷和正电荷的对应物进行了系统的理论研究。采用了不同的理论方法，即密度泛函理论（DFT）、二阶Møller-Plesset微扰理论（MP2）以及耦合簇单双激发，包括非迭代三激发[CCSD(T)]，并结合6 - 311+G(2df)基组。除了阳离子GaSe4和Ga2Se4外，镓硒化物的最低能量构型倾向于为平面结构。使用CCSD(T)//B3LYP理论水平，Ga(m)Se(n)（m = 1、2且n = 1 - 4）团簇的绝热电子亲和能（AEA）范围为1.07至3.78 eV，其绝热电离势（AIP）在7.57至8.76 eV之间变化。研究发现，镓硒化物的AEA不仅取决于团簇的亲电性，还取决于其电子结构。在单镓硒化物和双镓硒化物系列中，随着团簇尺寸的增加，AIP值和HOMO - LUMO（H - L）能隙未观察到明显趋势。在解离通道中，发现GaSe4→GaSe2 + Se2的分解在热力学上最有利。此外，发现GaSe2、GaSe3、GaSe4和Ga2Se4的AEA超过氯原子的AEA，因此被称为“超卤素”。最后，发现Ga2X(n)（X = O - Se；n = 2 - 4）系列中的AEA几乎相似。
