[Spectral Study of LaCl3 in Aqueous Solutions].

In this study, the Raman and fluorescence spectra of LaCl3 solution were studied with theoretical calculation and spectroscopic experiments. Based on B3LYP method of density functional theory, with the 6-31G(D,P)+Def2-SV (P) based on the group level the lanthanum chloride solution of micro cluster structure is calculated. The results show that the micro cluster molecules tend to form a 9 coordination structure, which verifies the feasibility of the method. Theoretical and experimental Raman values are compared to the basic consistent. The addition of LaCl(3) leads to the increase of the peak intensity of the Raman spectra in the 300~600 cm-1 range, which may be caused by the superposition of the La-O vibration and the rocking peaks of O­H in aqueous solutions; In the 3 000~4 000 cm(-1) range, the peak of lanthanum chloride solution is narrow compared with water, which may be caused by the stretching vibration of O­H in lanthanum hydrate. Fluorescence emission spectra at 350 nm appear obvious new peak, the good linearity was obtained between the peak intensity and the concentrations, and a rapid method for the quantitative analysis of lanthanum chloride solution from the angle of the complex is also realized. On the same basis set level calculated fluorescence emission center of clusters, in the range of allowable error, the theoretical calculation and the experimental spectra are basically consistent, and the new peak of the experimental spectra are identified.

[[Zn-(CH3CH2OH)n]2+ Clusters Probed with Fluorescence Spectroscopy and Computation].

In this paper the cluster structures of [Zn-(CH3CH2OH)n]2+ have been investigated with spectroscopic experiment and theoretical calculation. According to the fluorescence spectroscopy experiments, the fluorescence peak of ethanol molecules was found between 275~330 nm. A new peak appeared between 350~380 nm after the metal ions (Zn2+) was added into ethanol solution due to the generation of new clusters of molecules, and the original fluorescence peak of ethanol molecules became weak owing to the destroyed structure of ethanol molecules induced by Zn2+. The cluster structures of Zn2+ in water solution were investigated by using different methods. By comparing the results, a more accurate and fast B3LYP method of DFT was found and applied to optimize the possible structures of [Zn-(CH3CH2OH)n]2+. The results suggested that the first solvation shell of the system is up to six ethanol molecules, and thermodynamic parameters also shows the six kinds of molecular clusters which are likely in the solution. Moreover compared the theoretical fluorescence spectroscopy with experimental fluorescence spectroscopy, new clusters [Zn-(CH3CH2OH)n]2+ have been generated, with [Zn-(CH3CH2OH)n]2+(n=1~3) as main constructions.

Continuous extremal optimization for Lennard-Jones clusters.

We explore a general-purpose heuristic algorithm for finding high-quality solutions to continuous optimization problems. The method, called continuous extremal optimization (CEO), can be considered as an extension of extremal optimization and consists of two components, one which is responsible for global searching and the other which is responsible for local searching. The CEO's performance proves competitive with some more elaborate stochastic optimization procedures such as simulated annealing, genetic algorithms, and so on. We demonstrate it on a well-known continuous optimization problem: the Lennard-Jones cluster optimization problem.