Dispersed fluorescence spectroscopy of jet-cooled DCO

We obtain dispersed fluorescence (DF) spectra of jet-cooled DCO from three excited-state levels in the B̃2A′-X̃2A′ system. These spectra yield term energies and relative fluorescence intensities for 112 levels (mostly quasibound resonances) of DCO (X̃) over an energy range of 0–19000 cm−1. We make zeroth-order, normal-mode vibrational assignments to 99 levels; however, their term energies are not well described by the customary (Dunham) expression due to extensive vibrational mixing and the weak CD bond. The use of an improved spectroscopic Hamiltonian that includes Fermi resonance and Darling-Dennison coupling terms is discussed.