Structural And Optical Properties Of Fused Silica Cluster

In high power laser,the design of high Power UV laser systems is limited to a large extent by the laser initiated damage(LID)performance of transmissive fused silica optical components.Therefore,the chief science issues facing is to enhance the resistance to optical components and to prolong the serviceable lifetime at present.In this paper,First-Principle method calculations based on time dependent density functional theory(TDDFT)have been performed to investigate electronic structure and optical properties of fused silica clusters with NBOHC-E' and ODC defects.The main contents are as follows:(1)The research on the choice of the exchange-correlation functional.During the fused silica cluster modeling and testing,we use different cluster sizes to select a reasonable size of fused silica cluster model.In addition,in order to improve calculation accuracy,we systematically test different exchange-correlation functional(GGA-PBE?GGA-PW91 and B3LYP),then analyze and contrast the test precision of the model and finally select hybrid functional(B3LYP)for further electronic structure and optical properties calculations on the system of fused silica cluster.(2)The research on the fused silica cluster model with NBOHC-E' defect.We calculate the energy barrier of the NBOHC-E' point defects using the functional B3LYP,clarify its preferable structure and electronic structure properties and analyze the optical absorption peak of different size clusters.The calculation results represent that:the optical absorption peak for Si2O7H6 and Si5O16H12 with NBOHC-E' defects are found at 2.66 eV,which has a blue shift phenomena compared with the bulk fused silica.Research in this area has been published in the Communications in Theoretical Physics in 2015.(3)The research on the fused silica cluster model with oxygen-deficiency centers(ODCs)defects.We systematically investigate the structural and optical properties of fused silica cluster with ODCs defects and analyze the interconversion between ODCs(? Si-Si ? bond and divalent Si)induced by UV irradiation.Our results are in qualitative agreement with the experiment and provide strong theoretical support to the viability of the processes.