Photoelectron Spectroscopy\nand Theoretical Studies\non the Structures and Properties of Ge<sub>4</sub>C<sup>–</sup> and Ge<sub>4</sub>CH<sup>–</sup> Clusters

We investigate the structures and properties of Ge<sub>4</sub>C<sup>–/0</sup> and Ge<sub>4</sub>CH<sup>–/0</sup> clusters\nusing anion photoelectron spectroscopy and theoretical calculations.\nOur calculations show that the first two low-lying isomers coexist\nin the experiments of Ge<sub>4</sub>C<sup>–</sup> and Ge<sub>4</sub>CH<sup>–</sup>. The first two low-lying isomers of\nGe<sub>4</sub>C<sup>–</sup> have trigonal bipyramidal structures\nwith the C atom on the equatorial plane and the top vertex, respectively.\nIt is found that the first two low-lying isomers of Ge<sub>4</sub>CH<sup>–</sup> can be obtained by adding an H atom to the\ntop and equatorial C atoms of Ge<sub>4</sub>C<sup>–</sup>,\nrespectively. The AdNDP analyses reveal that the C atom in Ge<sub>4</sub>C forms one 4c-2e σ bond, two 4c-2e π bonds, and\none 5c-2e σ bond with Ge atoms. The C atom in Ge<sub>4</sub>C interacts with an H<sup>–</sup> forming a C–H σ\nbond in Ge<sub>4</sub>CH<sup>–</sup>. AIMD simulation results\nindicate high dynamic stabilities of Ge<sub>4</sub>C and Ge<sub>4</sub>CH<sup>–</sup> at 300 and 500 K. Our results show that the\nstructures and chemical bonding of Ge<sub>4</sub>B<sup>–</sup> and Ge<sub>4</sub>N<sup>+</sup> are similar to those of Ge<sub>4</sub>C, while those of Ge<sub>4</sub>BH<sup>2–</sup> and Ge<sub>4</sub>NH resemble those of Ge<sub>4</sub>CH<sup>–</sup>.