Characterization of the intermolecular vibrational levels bound within the Ar + I₂(E, v) potential energy surfaces

Two-color, two-photon laser-induced fluorescence experiments were performed to probe the intermolecular interactions within the Ar + I₂(E, v_E = 0–3) potential energy surfaces. Spectra were recorded using the lowest-energy T-shaped level and an excited intermolecular vibrational level with bending excitation within the Ar + I₂(B, v_B = 23) potential as intermediate levels to guide the spectral assignments. Progressions of intermolecular stretching and bending levels bound within the Ar + I₂(E, v_E) potentials were identified, and their vibrational frequencies were determined. The harmonic frequency and anharmonic constant for the bending vibrational mode were determined to be ωₑ(b) ∼ 34.8 cm⁻¹ and ωₑχₑ(b) ∼ 0.3 cm⁻¹. The frequency and anharmonic constant for the stretching mode were found to be the same as reported previously [V.V. Baturo, et al. Chem. Phys. Lett. 647 (2016) 161], ωₑ(s) = 37.2(1.1) cm⁻¹ and ωₑχₑ(s) = 1.8(2) cm⁻¹.