Fourier transform infrared isotopic study of linear CrC3: Identification of the nu1(sigma) mode.
A vibrational fundamental of linear CrC3 has been detected in the products from the laser ablation of chromium and carbon rods trapped in solid Ar at approximately 10 K. Fourier transform infrared measurements of frequencies and 13C isotopic shifts are in very good agreement with the predictions of density functional theory calculations at the B3LYP6-311G+(3df) level, resulting in the identification of the nu1(sigma) stretching mode at 1789.5 cm(-1). This is the first optical detection of the linear isomer of the transition-metal carbide CrC3 for which previous photoelectron spectroscopic studies have reported evidence of both linear and cyclic isomers.