Rotational and ro-vibrational transitions of He2C2+

Abstract

Ab initio calculations of transition frequencies and line strengths have been calculated for the “forbidden” rotational spectrum and ν₂ fundamental ro-vibrational of the ¹A₁ state of He₂C²⁺. For the “pure” rotational spectrum, the vibration ground state transitions are very weak, with the intensity of the strongest line, 3₃₁–4₄₀, being only 2.15 × 10⁻²² cm molecule⁻¹. A group of significant line strengths is attributed to ro-vibrational transitions between (〈0,2,0〉 ←〈0,1,0〉) and (〈0,1,0〉 ← 〈0,0,0〉) bands. These band centers are calculated at 309.5 and 330.4 cm⁻¹ respectively. The strongest band is identified with the (〈0,2,0〉 ← 〈0,0,0〉) transition with a band center of 625.1 cm⁻¹ and line strength of 2.58 × 10⁻¹⁹ cm molecule⁻¹ for the (4₄₀ ← 4₄₁) transition.