Electronic states of some simple ethers studied by vacuum ultraviolet absorption and near-threshold electron energy-loss spectroscopy

Abstract

Vacuum ultraviolet absorption spectra (250–105 nm, 5–11.8 eV) and near-threshold electron energy-loss spectra (0 eV–E_i,1) have been recorded for dimethyl ether (1), diethyl ether (2), tetrahydrofuran (3), 1,4-dioxane (4) and 3,4-dihydropyran (5). For the saturated compounds 1–4 the low-lying electronically excited states are predominantly Rydberg in nature, selectively mixed with valence-excited states. Also, the lowest triplet state in each of the saturated molecules is within 0.5 eV of the ¹n_O 3s state. The spectra of 5 resemble those of unsaturated hydrocarbons; its lowest triplet state (³ππ*) is ca. 4.2 eV.