The ν2 + ν4 and 2ν2 + ν5 high resolution infrared bands of FClO3

Luciano Fusina (1) , Elisabetta Canè (1) , Riccardo Tarroni (1) , Klaus Burczyk (2)

1 Dipartimento di Chimica Fisica e Inorganica [Bologna]
2 Anorganische Chemie

The high resolution infrared spectra of the mono isotopic species F35Cl16O3, F37Cl16O3, F35Cl18O3 and F37Cl18O3 have been analysed in the region of the ν2 + ν4 and 2 ν2 + ν5 perpendicular combination bands, from 1920 to 2060 cm-1. Both bands are perturbed by the anharmonic interaction effective between the v2 = v4 = 1 and v2 = 2, v5 = 1 excited states of E symmetry. The ν2 + ν4 bands are of medium strong intensity while the 2ν2 + ν5 ones are very weak. Since the origins of the two bands differ by about 10 cm-1, the 2ν2 + ν5 bands at lower wavenumbers are almost completely hidden by ν2 + ν4. In total, about 3400, 2400, 2800 and 3200 transitions have been assigned for F35Cl16O3, F37Cl16O3, F35Cl18O3 and F37Cl18O3, respectively. The assignments of each dyad have been analysed simultaneously with the inclusion of the anharmonic resonance term in the model Hamiltonian. The ro-vibration parameters of the v2 = v4 = 1 and v2 = 2, v5 = 1 excited states have been obtained, together with the deperturbed band origins and the anharmonic resonance coefficients . Combining the ν2 + ν4 origins with those of the ν2 and ν4 fundamentals, the anharmonicity constants have been derived for the four molecules and compared to the ab initio values calculated taking into account the Fermi resonance.

Mots clés: Physical Sciences

Domaines: Matière Condensée [cond-mat]

Luciano Fusina, Elisabetta Canè, Riccardo Tarroni, Klaus Burczyk. The ν2 + ν4 and 2ν2 + ν5 high resolution infrared bands of FClO3. Molecular Physics, 2011, 109 (17-18), pp.1. ⟨10.1080/00268976.2011.609137⟩. ⟨hal-00728419⟩