Gas phase detection of cyclic B3: 2(2)E' <-- X2A1' electronic origin band

The rotationally resolved origin band in the 2(2)E'<--X2A1' electronic spectrum of cyclic B3 has been observed by cavity ring down spectroscopy in the gas phase. The B3 molecule was generated in a supersonic planar plasma containing decaborane (B10H14) and neon as a carrier gas. The rotational structure pattern is that of a cyclic molecule. It is analyzed assuming an equilateral triangle in both electronic states. The band origin is determined to be 21 853.52 cm(-1), and the bond lengths 1.603 77(106) A in the ground and 1.619 07(96) A in the excited electronic state are inferred from analysis of the rotational structure.