CNDO‐MO calculation of N_nF_m molecules

Abstract

The .A-p separation model C N D O -M O method has been introduced and developed for both the open-and closed-shcli systems since 1975. This method has two chief advantages over most of the other CYDO methods. ( I ) The ns and np bases of the same atom may be considered independent 10 infer different bonding behavior.(2) Pariser-Parr and Nishimoto-Mataga approximations are .ippiied to the Coulombic repulsion integrals, which not only simplifies the calculation and saves computer time but also gives reliable computational results. A series of nitrogen fluoride molecules \uch ;is Y F. NFz. N F!. cis-NzFz, rrun.c-ICzFz, and NzF4 have been selected for this MO calculation.In cnch case. both ionization potential and dipole moment were calculated. The results are closer to thc observed values than those reported in other works. Z , ' P p p ) , bond parameter (By), etc. The numerical value of I (or k ) represents the order in which the azimuthal quantum number set is counted in the whole M O system, and such set contains one or more than one AO while is indexed by p. When index I (or k ) is used, atom A (or B ) is implied. The derivation and the detailed discussion of this method are given in Ref. 1 . With this modification, the core matrix and Fock matrices of both the closed-and open-shell systems arc as follows: