UV Photoelectron Spectra and Pseudopotential “ab initio” Calculations of Some 4-Membered Cyclic Amides of Group XIV Elements

Gas-phase He I and He II photoelectron spectroscopy and Pseudopotential “ab initio” calculations were used to determine the electronic structure of some 4-membered cyclic amides containing Si, Sn and Pb. The IE splitting on the non-bonding nitrogen-localized m .o .s ., nN asym(a2) and nN sym(b2), due to the “through space” interaction is critically affected by the planar ring molecular structure and the coordination of the silicon and tin atoms of the ring. The pseudopotential “ab initio” model resulted successful in describing the electronic structure of the molecules containing heavy atoms, at a Koopmans’ approximation level.