Laboratory Detection of a Bent-Chain Carbene Isomer of C[TINF]6[/TINF]H[TINF]2[/TINF]

Abstract

The rotational spectrum of a bent singlet isomer of the carbene, a carbon chain that has been observed C H 6 2 in the laboratory and in space, was detected in a supersonic molecular beam by Fourier transform microwave spectroscopy. The three rotational constants and the leading centrifugal distortion constants were determined to high accuracy, allowing the entire rotational spectrum of this molecule below 120 GHz to be calculated to a fraction of 1 km s Ϫ1 in equivalent radio velocity. The spectroscopic constants agree well with those recently calculated from high-level ab initio methods by Sattelmeyer & Stanton. Although bent is calculated to lie C H 6 2