It has been mentioned in L163-164 in the manuscript. Randic (1975) proposed molecular branching index χ, hereinafter referred to as simple molecular connectivity index (1995). Therefore, they are the same concept. [38] Randic M., Razinger M. (1995). Molecular Topograhic Indices. Journal of Chemical Information and computer Sciences. 35: 140-147. [40] Randic M. (1975). On Characterization of molecular branching. Am. Chem. Soc. 97: 6609-6615.
Is the explanation of χ is for molecular connectivity indices or branching index?