Cluster structure and anion size effects on charge-transfer-to-solvent states in X－(H2O)n=2-6 (X=Cl, Br, I) clusters

• Main Authors: Yuh-Tzung Liu, 劉育宗
• Other Authors: Wen-Shyan Sheu
• Format: Others
• Language: zh-TW
• Published: 2002
• Online Access: http://ndltd.ncl.edu.tw/handle/45554442993095570802

碩士 === 輔仁大學 === 化學系 === 90 === The study of charge-transfer-to-solvent (CTTS) phenomena of halide water cluster anions is helpful in exploring the fundamental interactions between solute and solvent molecules and their properties from the microscopic points of view. Because of the small and simple atomic structures of halide anions, halide water cluster anions have become prototypes in studying various factors affecting CTTS phenomena. In this thesis, the ab-initio method at the MP2 theoretical level is adopted to calculate the ground and excited state energies (ECTTS) of halides and their vertical binding energies (VBE) of the first excited states in several halide water clusters. After careful comparison and discussions of the results, the effects of the cluster structures and the anionic sizes on CTTS states become better understood. The results show that cluster dipole moments increase with the sizes of water molecule structures. The vertical excited energies of the ground states are correlated with the ionization potentials of the bare anions and the dangling hydrogen number of water molecules pointing toward the halide anions. The effect of cluster dipole moments on the ground vertical excited energies is less as significant. By increasing water cluster structures (and keeping the anions intact), the ECTTS is found reducing but the VBE is found increasing. On the other hand, if only changing the halides (and keeping water cluster structures the same), the ECTTS and VBE both decreases with the sizes of the halides. For the corresponding water cluster anions, the VBE decreases with the increasing sizes of the corresponding halide water cluster equilibrium structures.