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The oriented-gas model based on the additivity hypothesis is widely used in predicting the macroscopic nonlinear optical susceptibility of a molecular crystal from molecular (hyper)polarizability calculations. The calculations at the HF level without electron correlation correction result in the underestimation of the hydrogen bond effect on the first hyperpolarizabilities to about 15% in the urea case.

Research has been conducted on trinuclear metal clusters M-(mu-S)-M', where M is Mo and W, and M' is Cu, Ag and Au. The authors have investigated these clusters via the use of density functional theory method, and have reported the results.

A CuO-based material Cu5V2O10 was successfully grown in a closed crucible using Sr(OH)2· 8H2O as flux. The structure of Cu5V2O10 can be viewed as being composed of two types of zigzag Cu-O chains running along the b- and c-axes, which shows a two-dimensional crosslike framework with 12-column square tunnels along the a-axis. Magnetic measurements show that Cu5V2O10 exhibits unexpected large magnetic anisotropy, which is the first time magnetic anisotropy energy of ~107 erg/cm3 in the CuO-based materials has been observed. The origins of large anisotropy are suggested to arise from strong aniso-tropic exchanges due to the particular bonding geometry and the Jahn-Teller distortion of Cu2+ ions. Further, the band structure investigated by the GGA+U method suggests that Cu5V2O10 is a semiconductor. [ABSTRACT FROM AUTHOR]