%A Bo Hyung Ryoo %T Influence of Phosphine and Halide Ligands on the Properties of Undecagold Nanoclusters %X Surface ligands are essential components of nanomaterial identity, as they passivate the surfaces of many nanomaterials. Traditionally, ligands were considered for their size- and shape- directing properties in nanoparticles. Besides their usage in syntheses to control the morphologies of the nanomaterials, various ligands were used in tuning the surface functionality of nanomaterials for many applications, ranging from drug targeting to nanosensors. Recently, identities of the surface ligands were found to influence nanomaterial chemical and physical properties, including enhancement of stability, catalytic behaviors, and photoluminescence. These old and new ligand- controllable properties (achieved by various ligand modification through synthetic organic chemistry routes) necessitate a fundamental understanding of the ligand effect on the nanomaterials. In order to take another stride towards having a fundamental understanding of the ligands on nanomaterials, we study influences of and halide ligands on undecagold nanoclusters (Au11NCs). With the small size, the suite of atomically precise Au11NCs is easily accessible synthetically and theoretically. In addition, the ligand influences are intensified due to having majority of the gold atoms oriented on the surface of Au11NCs interacting with surface molecules. Systematically altering the type and composition of the surface ligands, which are subsequently characterized and compared with the local and overall electronic structures of computationally modelled Au11NCs, provides critical information about the ligand?s role in nanomaterials. Further, several overarching theories are suggested to elucidate the influence of the ligand identities on the enhancement of photoluminescence properties in Au11NCs. From this work, the mechanisms underlying ligand influence on Au11NCs can be translated to commonly used, larger nanoparticles and in the design of next-generation applications of nanomaterials. %D 2019 %K Nano, Nanocluster, Photoluminescence, Gold, Ligands, CP2K %I University of Pittsburgh %L pittir37132