The high resolution infrared bands ν 1, ν 2, ν 4 and ν 2 + ν 5 of F37Cl16O3

Abstract: The high resolution infrared spectrum of mono-isotopic F37Cl16O3 has been studied in the regions of ν 1, ν 2, ν 4 and ν 2 + ν 5 bands, centered at 1060.20, 707.16, 1301.71 and 1292.15cm−1, respectively. The ν 1 and ν 2 parallel bands are unperturbed so their analysis was straightforward and 3355 and 2433 transitions were assigned, respectively. The band origins, the rotational and centrifugal molecular constants in the v 1 =1 and v 2 =1 states have been determined, with standard deviation of the fits σ =0.00019 and 0.00018cm−1. The ν 4 fundamental is affected by an anharmonic resonance with the ν 2 + ν 5 combination band. The kl >0 sublevels cross at kl ⩾27 because of the opposite values of and . The anharmonic resonance constant cm−1 has been derived. The Δl =Δk =±2 and Δl =0, Δk =±3 essential resonances have been found to be effective in ν 4, while in ν 2 + ν 5 only the Δl =Δk =±2 one was active. A total of 5721 transitions have been assigned, 25% of them belonging to ν 2 + ν 5. The rovibrational parameters and the interaction constants of F37Cl16O3 have been obtained. The standard deviation of the fit is 0.0006cm−1, six times the estimated data precision. The equilibrium geometry of perchloryl fluoride has been determined from the A e and B e constants of F35Cl16O3 and F37Cl16O3. Using the A 0 and B 0 constants of all the symmetric species the r 0 geometry has also been derived. [Copyright &y& Elsevier]