Characterization of gas phase WC2+: a thermodynamically stable carbide dication
Résumé
Using an ab initio methodology, we performed a detailed theoretical study of the gas phase WC2+ dication.
These calculations were done using a multiconfigurational method in connection with a large basis
set, where relativistic effects were taken into account. This dication is identified here as the first
thermochemically stable doubly charged diatomic carbide in the gas phase. Our work hence confirms
the stability of this dication in the gas phase and its earlier observations by atom probe mass
spectrometry. Our calculations show that the shape of the potential energy curves of its lowest
electronic states changes drastically upon consideration of relativistic effects. For instance, the
electronic ground state possesses a Morse-like potential without spin–orbit that evolves to the usual
volcanic behavior, and with a columbic 1/R evolution at large internuclear separation after inclusion of
spin–orbit. We predict a set of thermochemical and spectroscopic data for this molecular species.