Dipole moments and orbital energies from ARCANA: A semi-empirical molecular orbital calculation program

Approximations employed in calculating two‐center nuclear attraction and electron repulsion integrals are discussed. A procedure for economical reduction of the number of integrals to be evaluated which satisfies the requirement of rotational invariance is discussed. This calculation technique is incorporated into a semiempirical molecular orbital calculation program and results in a realistic account of the anisotropy of atoms in molecules of low symmetry. Good agreement is found between electric dipole moments and molecular orbital energies determined experimentally and calculated employing ARCANA.