Electronic Spectra of MgC 2 n H ( n  = 1–3) Chains in the Gas Phase

Abstract

Electronic transitions of MgC 2n H (n = 1-3) have been observed in the gas phase in the visible region. A massselective, resonant two-color two-photon ionization technique, coupled with a laser ablation source, was used. Ab initio calculations of the geometries, energies, and vertical electronic excitations have been carried out using hybrid density functional theory and the coupled-cluster approach. The spectra are assigned as the A 2 II ←-X 2 Σ + electronic transition of linear chains. The origin bands are located at 4383,4453, and 4525 Å for MgC 2 H, MgC 4 H, and MgC 6 H, respectively, and provide a means of detecting such species in astronomical environments. © 2008. The American Astronomical Society. All rights reserved.