Single vibronic level emission spectroscopy and fluorescence lifetime of the B∼1A″→X∼1A′ system of CuOH and CuOD

Electron velocity map imaging and theoretical study on CuXH (X=O and S) anions

Vibrationally resolved photoelectron spectra of CuOH^- and CuSH^- have been determined via velocity map imaging method to investigate the transitions of X¹A'←X²A' at 532nm. Adiabatic detachment energies of CuOH^- and CuSH^- are assigned to 0.995(12) and 1.098(12) eV, respectively. Combined theoretical calculations with Franck-Condon simulations, it allows extracting the vibrational frequencies in neutral, which yields 629(32) cm^-1 with CuO stretching mode and 387(24) cm^-1 with CuS stretching mode for CuXH (X=O and S). Parallel transition properties of photoelectron angular distributions (PADs) for both species are correlated to the photodetachment of SOMO orbitals, which mainly involved in the Cu atom s orbital and partial s orbital in other atoms. Based on chemical bonding analyses (Wiberg, NAO, Mayer, NRT, and ELF), it is suggested that a trend is observed with a subtle variation of covalent component from weak covalent behavior between CuO in CuOH^-1/0 to stronger covalent bonding between CuS in CuSH^-1/0 (especially for non-ignorable covalent component in CuSH species) though ionic bonding dominates both in CuO and CuS bonds for the two systems.

Towards a quantum chemical protocol for the prediction of rovibrational spectroscopic data for transition metal molecules: Exploration of CuCN, CuOH, and CuCCH

High accuracy electronic structure computations for small transition metal-containing molecules have been a long term challenge. Due to coupling between electronic and nuclear wave functions, even experimental/theoretical identification of the ground electronic state requires tremendous efforts. Quartic force fields (QFFs) are effective ab initio tools for obtaining reliable anharmonic spectroscopic properties. However, the method that employs complete basis set limit extrapolation ("C"), consideration of core electron correlation ("cC"), and inclusion of scalar relativity ("R") to produce the energy points on the QFF, the composite CcCR methodology, has not yet been utilized to study inorganic spectroscopy. This work takes the CcCR methodology and adapts it to test whether such an approach is conducive for the closed-shell, copper-containing molecules CuCN, CuOH, and CuCCH. Gas phase rovibrational data are provided for all three species in their ground electronic states. Equilibrium geometries and many higher-order rovibrational properties show good agreement with earlier studies. However, there are notable differences, especially in computation of fundamental vibrational frequencies. Even with further additive corrections for the inner core electron correlation and coupled cluster with full single, double, and triple substitutions (CCSDT), the differences are still larger than expected indicating that more work should follow for predicting rovibrational properties of transition metal molecules.

First-principles calculations of the electronic and geometrical structures of neutral [Sc,O,H] molecules and the monocations, ScOH(0,+) and HScO(0,+)

Using multireference configuration interaction and coupled-cluster methodologies, with quadruple-ζ basis sets, we explored the potential energy surfaces of the ground and excited states of the neutral and cationic triatomics [Sc,O,H](0,+). In its ground state, the neutral species is trapped into either a linear ScOH or a bent HScO conformation; these two minima are approximately equal in energy and separated by a barrier of 40 kcal/mol. The linear ScOH structure is preferred by the excited states of the neutral species and by all of the electronic states of the charged molecular systems that we studied in this work. Both ScOH and ScOH(+) present ionic characters, Sc(+)OH(-) and Sc(2+)OH(-), similar to those found for the isovalent ScF(0,+) species. The HScO(0,+) structures are obtained by covalent or dative interaction of hydrogen and ScO(0,+). For most of the minima located in this work, we calculated geometries, vibrational frequencies, binding energies, excitation energies, and dipole moments. Our numerical results agree well with existing experimental data.