Electronic Absorption Spectra of BC, BC^-, BC₂, and B in Neon Matrices

Abstract

The electronic absorption spectra of BC, BC2 and their anions were detected in 5 K neon matrices. After mass-selected co-deposition of BC- with excess of neon, an absorption system with origin at 622.7(2) nm is observed and assigned to the A 1Σ+ ← X 1Σ+ electronic transition of BC-. Irradiation of the matrix leads to photodetachment, and the known B 4Σ- ← X 4Σ- electronic transition of BC, as well as a new one C 4Π ← X 4Σ- with origin at 291.0(2) nm, are observed. Measurements with mass-selected B lead to the identification of the A 1Π ← X 1Σ+ electronic transition of linear B at 432.2(2) nm. Subsequent neutralization leads to the appearance of two new systems with origin at 851.4(2) and 1587.8(2) nm of either linear and/or cyclic BC2. In the infrared the ν1 band of linear B was observed at 1936.3(1.0) cm-1 and after irradiation the ν2 band of cyclic BC2 at 1196.8(1.0) cm-1.