Force field calculations of acetonitrile using CNDO/force method

Abstract

The redundancy-free internal valence force field (RFIVFF) of acetonitrile is reported using CNDO/force method. The initial force field is set up by taking the interaction and bending force constants from CNDO force field and transferring stretching force constants from the force fields of chemically related molecules. The final force field is obtained by refining the initial force field using vibrational harmonic frequencies of CH₃CN, ¹³CH₃CN, CH₃¹³CN, CH₃C¹⁵N, CD₃CN and CD₃¹³CN. The final force field thus obtained is found to be excellent on the basis of frequency fit and potential energy distribution.