2Π–X2Σ+Electronic Bands of Titanium Methylidyne, TiCH, near 725 nm Wavelength

• Published in: Journal of molecular spectroscopy Vol. 181; no. 1; pp. 168 - 179
• Main Authors: Barnes, M., Merer, A.J., Metha, G.F.
• Format: Journal Article
• Language: English
• Published: Elsevier Inc 01.01.1997
• ISSN: 0022-2852; 1096-083X
• DOI: 10.1006/jmsp.1996.7179

Electronic bands assigned to the linear TiCH and TiCD radicals have been recorded by laser-induced fluorescence in the 620–725 nm wavelength region, following the reaction of laser-ablated Ti atoms with methane under supersonic jet-cooled molecular beam conditions. Rotational analyses of high-resolution spectra have given the ground state substitution structureX̃Σ+:r0(C–H) = 1.085 ± 0.002 A;r0(Ti–C) = 1.7277 ± 0.0003 A. The electronic upper state appears to be a very strongly perturbed2Π state, with many extra rotational and vibrational levels appearing; it has not been possible to make vibrational assignments, though the Ω′ values have been established for some of the levels. Wavelength-resolved fluorescence spectra have given two of the three ground state vibrational frequencies:TiCH: ν2(bend) = 578 cm−1, ν3(Ti–Cstretch) = 855 cm−1TiCD: ν2= 442 cm−1, ν3= 815 cm−1. Vibrationally forbidden transitions to the ground state bending fundamental appear prominently in many of these spectra, as a result of strong vibronic coupling. No evidence for ν1″(the C–H stretching vibration) has been found.