Electronic structure and spectra of small rings. VI. Multiphoton ionization spectra of the saturated threehyphen;membered rings

摘要

The multiphoton ionization spectra of cyclopropanehyphen;h6, cyclopropanehyphen;d6, and ethylenimine have been recorded, and the resonances observed at the twohyphen;photon levels compared with the corresponding singlehyphen;photon transitions. In the cyclopropanes, a complex band system is observed in the twohyphen;photon 51thinsp;000ndash;56thinsp;000 cmminus;1region which is shown to be electronically allowed lsqb;origins at 51thinsp;059 cmminus;1(minus;h6) and 51thinsp;109 cmminus;1(minus;d6)rsqb; for both onehyphen;photon and twohyphen;photon absorption, and to be due to the 3eprime;rarr;3sRydberg transition. The1Eprime; state is strongly Jahnndash;Teller distorted, with conspicuous display ofeprime; ring deformation in the Franckndash;Condon envelope. In ethylenimine, the 8aprime;rarr;3sband is structured in the twohyphen;photon spectrum, but not in one. A second band is also found near 55thinsp;000 cmminus;1which does not coincide in detail with the onehyphen;photonnrarr;3pband in the same region, and is thought to be a second component of the (n,3p) manifold.