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Full-Text Articles in Chemistry

Synthesis, Characterization, And Catalytic Activity Of Copper Palladium Oxide Solid Solutions., Gregory L. Christensen Dec 2018

Synthesis, Characterization, And Catalytic Activity Of Copper Palladium Oxide Solid Solutions., Gregory L. Christensen

Department of Chemistry: Dissertations, Theses, and Student Research

CuxPd1-xO forms a homogeneous solid solution over the wide range of 0 ≤ x ≤ 0.725 in which compositional variation can be correlated with structural and chemical environmental changes. After a small lag at low Cu2+ concentrations, where the lattice cell parameters are pinned to that of the pure PdO structure, CuxPd1-xO lattice parameters follow Vegard’s law in which the cell volume decreases linearly with x, indicating a homogenous solution in which Cu2+ randomly replaces the larger Pd2+ cation. The crystal structure also undergoes an increase in the c/a …


Global Minimum Search And Carbon Monoxide Binding Studies Of Novel Gold Nanoclusters, Navneet S. Khetrapal Nov 2018

Global Minimum Search And Carbon Monoxide Binding Studies Of Novel Gold Nanoclusters, Navneet S. Khetrapal

Department of Chemistry: Dissertations, Theses, and Student Research

In bulk form, gold is a well-known noble metal. However, gold nanoparticles exhibit remarkable catalytic behavior towards various types of chemical reactions. These catalytic properties are highly dependent upon the size and shape and therefore knowledge of the geometries of these nanoparticles is of prime importance. The main goal of this dissertation is, therefore, going to be towards the elucidation of the structures of novel gold clusters using a combined experimental and theoretical approach and subsequent modeling to explore the binding of simple substrates like carbon monoxide with gold clusters. The theoretical method used to study the structural evolution of …


Abnormal Phase Transition Between Two-Dimensional High-Density Liquid Crystal And Low-Density Crystalline Solid Phases, Wenbin Li, Longjuan Kong, Baojie Feng, Huixia Fu, Hui Li, Xiao Cheng Zeng, Kehui Wu, Lan Chen Jan 2018

Abnormal Phase Transition Between Two-Dimensional High-Density Liquid Crystal And Low-Density Crystalline Solid Phases, Wenbin Li, Longjuan Kong, Baojie Feng, Huixia Fu, Hui Li, Xiao Cheng Zeng, Kehui Wu, Lan Chen

Xiao Cheng Zeng Publications

Some two-dimensional liquid systems are theoretically predicted to have an anomalous phase transition due to unique intermolecular interactions, for example the first-order transition between two-dimensional high-density water and low-density amorphous ice. However, it has never been experimentally observed, to the best of our knowledge. Here we report an entropy-driven phase transition between a high-density liquid crystal and low-density crystalline solid, directly observed by scanning tunneling microscope in carbon monoxide adsorbed on Cu(111). Combined with first principle calculations, we find that repulsive dipole–dipole interactions between carbon monoxide molecules lead to unconventional thermodynamics. This finding of unconventional thermodynamics in two-dimensional carbon monoxide …


Structural Evolution Of Gold-Doped Bismuth Clusters AubiN (N = 4−8), Seema Pande, Tian Jian, Navneet S. Khetrapal, Lai-Sheng Wang, Xiao Cheng Zeng Jan 2018

Structural Evolution Of Gold-Doped Bismuth Clusters AubiN– (N = 4−8), Seema Pande, Tian Jian, Navneet S. Khetrapal, Lai-Sheng Wang, Xiao Cheng Zeng

Xiao Cheng Zeng Publications

The structures of gold-doped bismuth clusters, AuBin (n = 4−8), are investigated through a joint photoelectron spectroscopy and density functional theory (DFT) study. Well-resolved photoelectron spectra are obtained at several photon energies. Global minimum searches coupled with DFT calculations yield low-lying structures, whose relative energies are further evaluated by single-point energy calculations at the CCSD(T) level of theory. Vertical detachment energies are calculated with the inclusion of spin−orbit effects to compare with the experimental data. Three-dimensional structures are found to be dominant in this size range, while a planar low-lying isomer is observed only for AuBi4 …