The h-index, introduced by Hirsch, is based on the mutual variation between the number of cited and source items. The temporally continuous nature of the citation accretion process causes a shift of cited items from the h-core zone to the adjacent citation-asymmetric zones, viz. h-excess zone, or h-tail zone. The name given to this shifting phenomenon is the Diffusion of Cited Items (DCI). In this paper, two new variables are introduced, i.e., the Fold of Excess citation over Total citations (FET), denoted by $\epsilon^2$ and the Fold of h-core citation over Excess citations (FHE), denoted by $\theta^2$. On the basis of $\theta$ and $\epsilon$, another indicator is introduced, i.e., the Citation Swing Factor (CSF), defined as $d\theta/d\epsilon$, which indicates the differential coefficient of $\theta$ with respect to $\epsilon$. The time dependence of FET and FHE is also discussed. The possible solutions of are derived here. The functionality of CSF ($d\theta/d\epsilon$) to measure the diffusion process quantitatively will be tested later on for journals, authors and institutions.