High-resolution FTIR spectrum of CH₂D⁷⁹Br: the ground,v₅=1 andv₉=1 state constants

High resolution synchrotron far-infrared study of CH2D79Br: The v6 fundamental and 2v6−v6, v5+v6−v6 and v6+v9−v6 hot bands

“…The experimental details of the measured spectrum in the v 5 and v 9 fundamentals are provided in [8].…”

“…The preparation of CH 2 D 79 Br was accomplished according to [8]. Preliminary tests on the sample purity established that the most abundant impurity is given by the 79 Br of CH 3 Br ($4%), while the relative abundance of the 81 Br isotopologue of CH 2 DBr should be lower than 1.5%, as explicitly stated in the specifications of the material used in the synthesis.…”

“…During the analysis of the v 6 fundamental band and as recognized in the v 5 and v 9 band regions [8], it became clear that the many weak unassigned lines belong to hot bands. Considering v 6 (v 0 = 595.0733 cm À1 ) as the lower level, the Boltzmann population at room temperature is 5.8% while that of the next higher level v 5…”

“…The rotational structure in the R branch appears very similar; the only difference is given by the opposite sequence of the asymmetry split lines observed up to K a 6 3. Assignment in the P and R branches near the band centre was performed by predictions based on the spectroscopic constants derived from [6,8] and subsequently checked by GSCDs. The transitions were fitted to obtain preliminary upper-state parameters then used to extend the data at increasing J and K a quantum numbers.…”

“…Since natural abundant CH 2 DBr is a mixture of almost equivalent percentages of 79/81 Br isotopologues (50.7% and 49.3%, respectively), the rovibrational spectra of this compound are very congested. In order to access the spectroscopic parameters of the molecule, a high-resolution infrared spectrum of an isotopically enriched sample of CH 2 D 79 Br has been analyzed in the region of the v 5 (A 0 ) and v 9 (A 00 ) fundamentals [8]. These bands of medium intensity give rise to a/b-type hybrid (v 5 ) and c-type (v 9 ) absorption features which, merging the ground-state combination differences (GSCDs), were deemed convenient for determining the groundstate constants.…”