Orthobaric Densities and Surface Tension of Carbonyl Sulfide.

General and physical chemistry

“…~~ He obtains the same set of equations as Lennard-Jones for the best wave function of the determinantal type (these equations are identical with the Hartree-Fock equations for atoms), but pays particular attention to the problem of obtaining the component molecular orbitals in LCAO form; that is, he sets out to find the best ones that can be constructed out of a given set of atomic orbitals. Mathematically his theory is very elegant, but in view of Coulson and Jacobs's work 28 there are doubts whether it goes far enough ; even if the best molecular orbitals are used configurational interaction cannot be ignored, and if this is to be taken into account one might as well begin from the simpler " inconsistent " orbitals-the final result must be the same. 3' Nevertheless, the self-consistent molecular-orbital method has been applied with encouraging results to some unsaturated systems : to cis-and trans-butadiene by Parr and M ~l l i k e n , ~~ who obtain good values for the lower excitation energies and ionisation potentials and find the trans-form to be 0-12 ev more stable than the cis-isomer ; to carbon dioxide by M~lligan,3~ who calculates the first two ionisation potentials, but confines his calculations to a single internuclear distance ; and to allene by Parr and Taylor,40 who calculate the ground-state energy as a function of twist, and conclude that the ethylene-allene twisting frequency ratio should be rather greater than d2, in disagreement with the most recent experimental assignments.…”