Positron Annihilation Mechanism Correlated with Microstructure of C60-Contained Chitosan  

作　　者：DAI Yi-Qun HE Chun-Qing LI Shi-Qing FANG Peng-Fei CHEN Yuan-Yin WANG Shao-jie 戴益群;何春清;李世清;方鹏飞;陈远荫;王少阶(Department of Physics,Wuhan University,Wuhan 430072;Department of Chemistry,Wuhan University,Wuhan 430072)

机构地区：[1]Department of Physics,Wuhan University,Wuhan 430072 [2]Department of Chemistry,Wuhan University,Wuhan 430072

出　　处：《Chinese Physics Letters》2000年第6期457-459,共3页中国物理快报（英文版）

基　　金：Supported by the National Natural Science Foundation of China under Grant No.29674020.

摘　　要：Positron annihilation lifetime spectra measurements were performed on C_(60)-containing chitosan as a function of temperature ranging from 290 to 380K.Both the ortho-positronium annihilation lifetimeт_(3) and its intensity Is increase with increasing temperature,however,the values of I_(3) in C_(60)-containing chitosan are smaller than that in pure chitosan,and the slope ofт_(3) with temperature is also suppressed after C_(60) linked.The existing three models for positron annihilation in polymer have been compared to analyze the experiment result.It is realized that only the spur reaction model,combined with the free volume model,can explain it satisfactorily.The ortho-positronium lifetime and intensity were affected by the local physicochemical environment of material,i.e.,free-volume structure,electron scavenging and trapping sites,etc.The linked C_(60) that play a significant chemical inhibition and quenching role on positronium formation and annihilation isfirst observed.The microstructure change brought by C_(60) group has also been discussed.

关 键 词：ANNIHILATION LIFETIME POSITRONIUM 

分 类 号：O57[理学—粒子物理与原子核物理]