Vibrationally resolved photoelectron spectroscopy is combined with ab initio calculations to investigate the structure and chemical bonding in AlC2- and AlCSi-. AlC2- was found to have a C2 structure whereas AlCSi- was found to be almost linear, thus establishing pi-coordination of Al in AlC2- and sigma-coordination in AlCSi-. The adiabatic electron affinities of AlC2 and AlCSi were measured to be 2.65(3) and 2.50(6) eV, respectively. The calculated vertical (2.87 eV) and adiabatic (2.60 eV) electron detachment energies for AlC2- agree well with the 2.73(0.03) and 2.65(0.03) eV experimental values, respectively. The calculated (2.86 eV) and experimental (2.64+-0.04 eV) vertical detachment energies for AlCSi- were also in good agreement. The calculated vibrational frequency for AlC2 and vertical detachment energies for other higher energy features in both AlC2- and AlCSi- were also in good agreement with the experimental measurements. The combined experimental and theoretical effort allows us to elucidate the structures of AlC2- and AlCSi- and the nature of their chemical bonding.
Revised: May 17, 2002 |
Published: November 3, 1999
Citation
Boldyrev A.I., J. Simons, X. Li, and L.S. Wang. 1999.pi- and sigma- Coordinated Al in AlC2- and AlCSi-. A Combined Photoelectron Spectroscopy and ab Initio Study.Journal of the American Chemical Society 121, no. 43:10193-10197.PNNL-SA-32453.