Mean Square Distance Topological Index

For acyclic graphs only, if in the above formula only distances between endpoints are taken into account, the related endpoint mean square topological index Df1 results. 

Both D(2) and D 2) decrease with increasing branching. Whereas D 2) induces in alkanes an ordering similar (but not identical) to that caused by I , D 2) gives an ordering resembling that induced by 1.  

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R is the topological radius, D the topological diameter, T the eccentricity, f the average atom eccentricity, At the eccentric, p2 the polarity number, and MS D the mean square distance index. 

Those based on the topological distance matrix, including the Wiener index, the polarity number, the distance sum, the Altenburg polynomial, the mean square distance, the Hosoya index, and the distance polynomial ... 

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