Anton Perdih,* Branislav Perdih
Mala vas 12, SI-1000 Ljubljana, Slovenia
 

Abstract
The best correlations of some Vij(m,n) indices using data from propane through all octanes are observed at Mw (r = 1), MR (r = 0.998), Tc2/Pc (r = 0.998), DHv (r = 0.997), BP (r = 0.994), Tc/Pc (r = 0.994), DHf°g (r = 0.991), and logVP (r = -0.990). The best correlations using only data of octanes are observed at Tc/Pc (r = -0.998), w (r =  0.996), BP/Tc (r =  0.995), MON (r = -0.987), Tc2/Pc (r = 0.984), C (r = 0.969), S (r =  0.961), and Pc (r = 0.950). The index Vij(-2,-2) has a regular sequence of isomers due to the increase of the size of the molecule. The indices Vij( 1/4, 6), Vij( 1,1/4), Vij(-2,1/4), Vij( 2,1/3), Vij(3, 1/4) as well as a group of Vij(m,n) indices having  1 Ł m Ł -1/4 and -1 Ł n Ł -1/4 have a regular sequence of isomers due to increasing branching. These indices seem to be good sources of the susceptibility for branching derived BIA type branching indices.