摘要
利用简正坐标方法研究了八面沸石TO_4四面体结构单元,通过实验及计算,发现键长、振动频率、Si/Al及键伸缩力常数之间存在良好线性关系,得到键伸缩力常数与Si/Al之间有如下关系: fr=-2.595N_(Al)/(N_(Al+N_(Si))+5.587同时发现变角力常数变化很小,键之间相互作用当Al成份增大时,由相互增强变为相互抑制。
The infared spectra of zeolites have been widely studied and the vibrational bands have been empirically interpreted as being characteristic of various 'internal' TO_4 motions and the motions of some 'external' linkages of the three-dimensional framework. We use the normal coordinate analysis to deal with the internal vibration and its varying with Si/Al ratio. We get the relationship between Si/Al and bond length as well as frequencies of asy. and sym.. By adjusting the force constants of stretching, bending and str-str interaction, we find the mutual linear relations between T-O stretching constants, bond lengths and Si/Al ratio, and we also find the change of the bending constants being very small.
