High resolution (e, 2e) spectroscopy of dimethyl ether

We report high-resolution (e, 2e) spectra of dimethyl ether (H3COCH3) in combination with high-level theoretical calculations. The observed binding energy spectra and momentum distributions were compared with Hartree-Fock, density functional theory (DFT), and symmetry-adapted-cluster configuration-interaction (SAC-CI) calculations. In general, the theoretical momentum distributions based on Dyson orbital (DO) and Kohn-Sham orbital (KSO) agree well with the experimental momentum distributions except the discrepancies in the low momentum regions of 2b1 and 1a2 orbitals. The present high resolution experimental data provide a benchmark for the future rigorous theories.