74508-07-9Relevant academic research and scientific papers
Emission spectra and electronic structure of group Illa monohalide cations
Glenewinkel-Meyer, Th.,Kowalski, A.,Mueller, B.,Ottinger, Ch.,Breckenridge, W. H.
, p. 7112 - 7125 (2007/10/02)
Optical spectra of ten AX+ ions (A = B, Al, Ga, In; X = F, Cl, Br) have been observed in the visible and near UV; a total of 18 band systems were newly discovered.The emission was produced by chemiluminescent reactions A+ + X2 at low (2-10 eVCM ) kinetic energy in a beam-gas arrangement.A position-sensitive photon counting detector with large surface area and very low dark count rate was employed, the resolution was mostly 5-50 Angstroem FWHM.Three types of band systems were observed: ( 1 ) For all AX+ combinations except BCl+ and BBr+, a very broad quasicontinuum with undulatory structure appears.On the basis of electronic state correlation arguments, photoelectron data, some ab initio calculations and, in one case, a known emission spectrum (InCl+ ) these band systems were identified as B2Σ+-X2Σ+ transitions.It is concluded that the excited state potentials are considerably displaced against the ground state, and their energetics are given. (2) For six species AX+, narrow band systems were observed in the 2500 Angstroem region.They could be clearly identified as being due to C2Π- X2Σ+ transitions by means of comparison with the systematics of the analogous A2Π-X2Σ+ transitions of the isoelectronic alkaline earth halides, by the resolved fine structure, and, in the case of AlF+, by an ab initio calculation. (3) In the GaCl+, GaBr+, and InBr+ spectra, narrow features accompany the C-X transitions.They are attributed to D2Σ+-X2Σ+ transitions, analogous to the alkaline earth halide B2Σ+-X2Σ+ band systems.Qualitative electronic state correlations are discussed, and the expected dominant configurations in different regions of the AX+ ground and excited states are given.These are in accord with recent ab initio results on AlF+.
