Multireference study of ionic/covalent electronic states of MF (M = Be, Mg and Ca)

Electronic Structure of Small Isolated and Supported Manganese Oxide Clusters

In the present work, possible molecular models of the isolated manganese oxides and supported Mn3Ox/Al2O3 structures were built based on small clusters of passivated MnOx. The support was represented as a simplified model of the alumina tetramer cluster based on small fragments of AlOxHy. Combinations of MnOxHy and AlOxHy clusters were made to form both the isolated and supported manganese oxides clusters. The electronic structure of these systems was characterized by ab initio methods (DFT and CASPT2). It was observed that the vertical excitation energy of the isolated and supported Mn3OxHy clusters is significantly lower than that of the alumina cluster model, while both the isolated and supported Mn3OxHy wave function characters are qualitatively similar with respect to the ground state and electronic transition processes, suggesting that the alumina cluster behaves as an inert support, since there is little contribution of this component in the description of the low-lying electronic states. The present study also reports for the first time the spectroscopic parameters of several clusters containing the manganese transition metal atom.

High resolution laser excitation spectra and Franck-Condon factors of A2Π−X2Σ+ electronic transition of MgF

Magnesium monofluoride (MgF) is proposed as an ideal candidate radical for direct laser cooling. Here, the rotationally resolved laser spectra of MgF for the A2Π− X2Σ+ electronic transition system were recorded by using laser induced fluorescence technique. The MgF radicals were produced by discharging SF6/Ar gas mixtures between the tips of two magnesium needles in a supersonic jet expansion. We recorded a total of 19 vibrational bands belonging to three sequences of Δ v=0, ±1 in the region of 348-370 nm. Accurate spectroscopic constants for both X2Σ+ and A2Π states are determined from rotational analysis of the experimental spectra. Spectroscopic parameters, including the Franck-Condon factors (FCFs), are determined from the experimental results and the Rydberg-Klein-Rees (RKR) calculations. Significant discrepancies between the experimentally measured and RKR-calculated FCFs are found, indicating that the FCFs are nearly independent of the spin-orbit coupling in the A2Π state. Potential energy curves (PECs) and FCFs determined here provide necessary data for the theoretical simulation of the laser-cooling scheme of MgF.