正电子湮没技术与沸石分子筛

Positron annihilation technique and zeolite

测量了３Ａ型及１３Ｘ型沸石分子筛在不同压强空气中的正电子寿命谱，并测量了１０Ｘ型分子筛在不同温度下焙烧后的寿命谱。测量表明：分子筛所吸附的气体对在其体内湮没的正电子有显著的影响．同时，沸石笼内水的存在也对其湮没参数有影响。研究表明，随着水的逐步脱除；笼内自由体积逐步增大；当脱水至一定程度后．笼内开始出现活性中心－质子酸。

The positron lifetime spectra have been measured as a function of exposed air pressure for synthetic zeolite 13X and 3A,and as a function of calcination temperature for zeolite 10X.It is found that the adsorbed gases have a strong effect on positron annihilation.Moreover,the positron annihilation parameters varysignificantly with the amount of water existing in the zeolite cages. With the dehydration the free volume inside cages bacame larger, and when dehydrated to a certain degree,Bronsted acid, as the active center,begin to appear.