Low-Temperature Rate Constants for Rotational Excitation and De- excitation of C sub(3) (X super(1)o1; [image]) by Collisions with He ( super(1)S)

The low-temperature rotational (de-) excitation of C sub(3) (X super(1)o1; [image]) by collisions with He ( super(1)S) is studied using an ab initio potential energy surface (PES). This PES has been calculated using the single- and double-excitation coupled-cluster approach with noniterative perturbational treatment of triple excitations [CCSD(T)] and the augmented correlation-consistent triple- zeta basis set (aug-cc-pVTZ) with bond functions. This PES is then incorporated in full close-coupling quantum scattering calculations for collision energies between 0.1 and 50 cm super(-1) in order to deduce the rate constants for rotational levels of C sub(3) up to j = 10, covering the temperature range 5-15 K.