Collection of Czechoslovak Chemical Communications - digital archive 

Abstract

A general quadratic force field has been calculated for the out-of-plane vibrations of pyrazine by the MINDO/3 method. The first derivatives of the energy were computed analytically and the second derivatives of energy numerically. The force constants so obtained have been refined to fit the observed frequencies of -h₄, -d₄ and cis-pyrazine-d₂. The calculations proved our assignment suggested previously, though the disagreement between theory and experiment for the A_u vibrations of pyrazine needs additional experimental and theoretical data for clarification.