Special issue: 22nd colloquium on high-resolution molecular spectroscopy HRMS Dijon 2011 (Part 2) the v_1+v_5 high resolution infrared band of FClO_3

摘要

The high resolution infrared spectra of the mono isotopic species F~(35)Cl ~(16)O_3, F~(37)Cl~(16)O_3, F~(35)Cl~(18)O_3 and F 37Cl 18O 3 have been analysed in the region of the v_1+v_5 perpendicular combination band, from 1540 to 1680 cm~(-1). For all the isotopologues the 1+5 band is of medium intensity at the recording conditions. In total, about 2400, 2000, 2600 and 2700 transitions have been assigned for F~(35)Cl ~(16)O_3, F~(37)Cl ~(16)O_3, F~(35)Cl ~(18)O_3 and F ~(37)Cl~(18)O_3, respectively. The data for each band have been analysed on the basis of the usual Hamiltonian for a degenerate state of a molecule of C3v symmetry. In addition, two interaction terms have been considered active within the v_1=v_5=1 state, with δl = 0,δk = ±3 and δl = δk =~(-2) selection rules. The ro-vibration parameters of the v_1=v_5=1 states have been obtained, together with the band origins. Combining the 1+5 origins with those of the 1 and 5 fundamentals, the anharmonicity constant x15 has been derived for the four molecules and compared to the corresponding value calculated ab initio.