Five electronic states (X 4S-, A 4?, B 4?, 2F, 2?) of the vanadium monochloride cation (VCl+) have been described using a focal point analysis (FPA) approach that conjoined a correlation-consistent family of basis sets up to aug-cc-pwCV5Z-DK with high-order coupled cluster theory through quadruple (CCSDTQ) excitations. Adiabatic excitation energies (T0) and spectroscopic constants (re, r0, Be, B0, e, we, v0, ae, wexe) were extrapolated to the valence complete basis set (CBS) Douglas-Kroll (DK) aug-cc-pV8Z-DK CCSDT level of theory, and additional treatments accounted for higher-order valence electron correlation, core correlation, and spin-orbit coupling. Due to the delicate interplay between dynamical and static electronic correlation, single reference coupled cluster theory is able to provide the correct ground electronic state (X 4S-), while multireference configuration interaction theory cannot. Perturbations from the first- and second-order spin orbit coupling of low-lying states with quartet spin multiplicity reveal immensely complex rotational data relative to the isovalent species VO, VS, and TiCl. Computational data on the doublet manifold suggest that the lowest-lying doublet state (2F) has a Te of ~12200 cm-1, while initial analysis of the experimental effective rotational Hamiltonian afforded a Te for a X 4S- ? 2S+ electronic transition of only ~350 cm-1. Resolution of this discrepancy is achieved by reanalysis of an improved effective Hamiltonian and assimilation of computed structural data into the effective Hamiltonian parameterization. Overall, this study shows that laboratory, observational, and theoretical rotational spectroscopy can confidently and reliably be performed in tandem to better understand the bonding and structure of inorganic molecules with astrochemical and astrobiological relevance.

Electronic structure of vanadium monochloride cation (VCl<sup>+</sup>): At the crossroads of experimental and computational astrochemistry

247th National Meeting (2014)

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Electronic structure of vanadium monochloride cation (VCl+): At the crossroads of experimental and computational astrochemistry

Electronic structure of vanadium monochloride cation (VCl⁺): At the crossroads of experimental and computational astrochemistry