Laser-Induced Fluorescence Spectroscopy of the BaNC Free Radical in a Supersonic Jet

Abstract

Laser-induced fluorescence spectra of the BaNC free radical in a supersonic jet have been recorded for the first time. A strong and rather complicated excitation spectrum was observed between 18 000 and 19 500 cm-1. In the corresponding dispersed fluorescence (DF) spectra, long progressions in the bending mode have been identified. The low frequency of this mode, 70 cm-1, for the fundamental demonstrates that BaNC is relatively floppy in the bending coordinate in its ground electronic state. The intensity profiles of the bending progressions suggest that BaNC undergoes a substantial change in its equilibrium bond angle on electronic excitation. This is most likely due to the formation of a bent structure in the excited electronic state. Ab initio calculations conducted in this work suggest that BaNC is linear in its ground electronic state. However, an apparent change in sign of the bending-mode anharmonicity, deduced from the DF spectra, is suggestive of a bent equilibrium structure with a small barrier to linearity.

Solvation of barium atoms and singly charged cations in acetonitrile clusters

“…The dominant BaNC + mass peak detected at 2.33 eV photoionization energy parallels observations made previously 33 Although the IE a 's of BaNC and BaCN calculated in this work, of 5.19 and 5.28 eV, respectively, are higher than that of Ba(CH 3 CN) 1 (IE a = 4.12 eV; see Table II) or BaOH (IE a = 4.55 eV; Ref. 29), the intensity of the mass peak corresponding to BaNC+/BaCN+ is the highest upon photoionization at 2.3 eV [ Fig.…”

“…4(c)] due to the fact that this wavelength is resonant with an excited electronic state (C 2 Π-X 2 Σ + ; Ref. 33) of neutral BaNC/BaCN. Instead, the signals from the other molecular species arise from less efficient, non-resonant MPI processes, thereby leading to lower intensities of the corresponding mass peaks.…”

New determination of the adiabatic ionization potential of the BaOH radical from laser photoionization-molecular beam experiments and ab initio calculations

“…These RECP's and their corresponding valence basis sets have been shown suitable to determine the geometries, harmonic frequencies, and IP a 's of small barium-containing species. 30,31,[36][37][38][39] Both the LANL2DZ RECP/valence basis set of Hay and Wadt 40 and the SDD quasirelativistic ECP/valence basis set of Kaupp et al, 41 as defined in the GAUSSIAN 03 package have also been evaluated for Ba.…”