Chord length distribution (CLD) could be used to describe the size, shape and arrangement of geometric figure, such as spheric particles, cylinder pore, thin sheets, etc. In principle, CLD is in proportion with the second derivative of correlation function obtained from small angle X-ray scattering (SAXS) and therefore can be calculated from the relative SAXS intensity. In structure research, the characteristics geometric information of particle can be obtained by comparing the experimental CLD from SAXS result and the theoretically predicted CLD with high precision. In this paper, with mesoporous molecular sieves as examples, the CLD method was introduced to calculate the size distribution of mesopores. The effect of surface organic functionaliztion of mseopores on pore size was also derived.

Key words: chord length distribution, small angle X-ray scattering, mesoporous molecular sieves