Detection of the tunneling-rotation transitions of malonaldehyde in the submillimeter-wave region

Abstract

The tunneling-rotation transitions of malonaldehyde, 43 a-type Q-branch lines, were observed in the submillimeter-wave region of 643–651 GHz. The proton tunneling splitting in the ground state, ΔE0=647 046.208±0.019 MHz, and the interaction constant, F=45.8965±0.0082 MHz, were determined, as well as the molecular constants for each tunneling sublevel.