THROUGH—SPACE AND THROUGH—BOND INTERACTIONS IN 1,5-CYCLOOCTADIYNE; THE ASSIGNMENT OF ITS PHOTOELECTRON SPECTRA

The through--space and through--bond interactions in 1, 5 -- Cyclooctadiyne arestudied. It is shown, with the assistance of improved MS--X_α method, that the through- spaceinteractions decrease with the distance of the orbitals, and both through--space and through--bondinteractions of 1, 5- Cyclooctadiyne are sizable but those two interactions oppose each othercausing the net splitting to be small for π_z orbital. The calculated ionization potentials are in goodagreement with the experiment of photoelectron spectra.