Vibrational Analysis of Some Substituted Methylbenzenes Part II. Transferability of Force Constants-The Case of Tetra-, Tri-methylbenzenes and Nitro-para-toluidine.

A zero-order normal coordinate analysis was made for 1,2,3,4-, 1,2,3,5-, 1,2,4,5-tetramethylbenzene, 1,2,3-trimethylbenzene and 2-nitro-para-toluidine by transferring the force constants from our earlier work. The observed and calculated frequencies agree with an average error of 16.4 cm-1. On the basis of the results obtained Unambiguous vibrational assignments of fundamentals of the five molecules have been made using the potential energy distributions and eigen vectors and several assignments suggested by earlier workers have been revised. [ABSTRACT FROM AUTHOR]