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1 INTRODUCTIONLow temperature phase barium metaborateβ- Ba B2 O4 ( BBO) as a new nonlinearoptical material was firstdiscovered in 1 979by Chen's group of the Fujian Instituteof Research on the Structure of Matter,People's Republic of China〔1〕.BBO has anumber ofexcellentpropertiessuch aslarge effective SHG coefficients,large birefrin-gence,wide transparent spectral range,high damage threshold and good machnicaland chemical properties.Particularly attractive feature is its UV t… 相似文献
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The local structure of β-BaB2O4 melt at 1400 K has been studied by using the method of molecular dynamics simulation. The radial functions simulated show agreement with the recent experimental results of X-ray diffraction. The calculation of bond order parameters indicates that the local structure of the melt can be described by the model of linear combination of 0.11 tetrahedrons BO4 and 0.89 planar triangles BO3. In the process of crystal growth the existing of many planar triangles BO3 in the melt maybe favorable for the forming of planar boroxol rings B3O6 near the crystal interface. The statistics of rings and chains have been done and some isolated BO3, pyroborate B2O5,chain(-B-O-)n and isolated B3O6 rings are found in the melt which is in agreement with HTRS experimental results. A large (-B-O-)n network is also found and it is suggested that the planar BO3 units are mainly existed in the network but isolated. 相似文献
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