Electronic structure and spectra of small rings. VI. Multiphoton ionization spectra of the saturated three-membered rings

Publisher Website
Google Scholar
Abstract
The multiphoton ionization spectra of cyclopropane‐h6, cyclopropane‐d6, and ethylenimine have been recorded, and the resonances observed at the two‐photon levels compared with the corresponding single‐photon transitions. In the cyclopropanes, a complex band system is observed in the two‐photon 51 000–56 000 cm−1 region which is shown to be electronically allowed [origins at 51 059 cm−1 (−h6) and 51 109 cm−1 (−d6)] for both one‐photon and two‐photon absorption, and to be due to the 3e′→3s Rydberg transition. The 1E′ state is strongly Jahn–Teller distorted, with conspicuous display of e′ ring deformation in the Franck–Condon envelope. In ethylenimine, the 8a′→3s band is structured in the two‐photon spectrum, but not in one. A second band is also found near 55 000 cm−1 which does not coincide in detail with the one‐photon n→3p band in the same region, and is thought to be a second component of the (n,3p) manifold.