Determination of the Born–Oppenheimer potential function of CCl+ by velocity modulation diode laser spectroscopy

Abstract

Over 70 transitions among the lowest six vibrational states of C³⁵Cl⁺ and C³⁷Cl⁺ have been measured between 1070–1210 cm⁻¹. The spectrum has been fitted to a sixth order Dunham expansion to yield an accurate mapping of the Born–Oppenheimer potential function of CCl⁺. The spectroscopic constants obtained are ω_e =1177.7196(8) cm⁻¹, ω_ex_e =6.6475(3) cm⁻¹, and B_e =0.797 940(3) cm⁻¹. The rotational constants for both CCl⁺ isotopes reported here show the results of the previous electronic emission studies to be incorrect. A fit of the data to a Morse function yields a dissociation energy D of 52 828(50) cm⁻¹. The rotational temperature has been determined as 540 K±30%. The increase in the effective vibrational temperature with vibrational excitation indicates that CCl⁺ is formed with high internal energy.