A correlated ab initio study of linear carbon-chain radicals CnH (n = 2-7)

Abstract

Linear carbon-chain radicals CnH for n = 2-7 have been studied with correlation consistent valence and core-valence basis sets and the coupled cluster method RCCSD(T). Equilibrium structures, rotational constants, and dipole moments are reported and compared with available experimental data. The ground state of the even-n series changes from 2Σ+ to 2Π as the chain is extended. For C4H, the 2Σ+ state was found to lie only 72 cm-1 below the 2Π state in the estimated complete basis set limit for valence correlation. The C2H- and C3H- anions have also been characterized. © 1995.