... D.; Haddon, RC In Carbonium Ions; Olah, GA, Schleyer, P. v. R., Eds.; Wiley: New York, 1976; Vol. ... 1981, 103, 5649); also see: The Carnegie-Mellon Quan- tum Chemistry Archive; 3rd ed.; Whiteside, R. A ... 0002-7863/89/ 15 1 1-3479$01.50/0 C 1989 American Chemical Society