Some INDO perturbation calculations of n J (NC) values

Standard INDO parameters are used in ‘sum‐over‐states’ perturbation calculations of n J (NC) in a variety of molecular environments. Good agreement with the experimental data is, in general, obtained when the integral products S N 2 (o) S C 2 (o) and 〈 r −3 〉 N 〈 r −3 〉 C assume the values of 35.167 a.u. −3 and 4.980 a.u. −3 , respectively. For ‘pyridine‐type’ nitrogen atoms the major contribution to n J (NC) usually arises from the orbital term whereas the contact term dominates the values of n J (NC) for ‘pyrrole‐type’ and amino nitrogen atoms.