A vibrational analysis of the gas phase i.r. spectrum of CHFCl2

Photolysis and Spectroscopy of Vibrationally Excited C−H Overtones of CHFCl2

“…The observed PA spectra represent not only contributions from the dominant isotopomers of CHFCl 2 but also contain transitions that are related to the hot bands observed in the fundamental region. , The CHFCl 2 comprises several fundamentals of low frequency < 1000 cm -1 , the lowest being the ClCCl bending, ν 6 (a‘) at 277.2 cm -1 . Therefore, ∼37% of the population are in these low vibrations at room temperature (compared to the zero point level population of 63%).…”

“…The CHFCl 2 is an asymmetric top (κ = − 0.59) that belongs to the C s point group for identical chlorine atoms and is reduced to C 1 for different chlorine isotopes. In the former, the ν 1 CH stretch and the ν 2 CH bend are of a‘ and the ν 7 CH bend of a‘ ‘ symmetry, while in the latter the CH stretch and bends are of type a. , From the rotational constants of the isotopomers with identical chlorine atoms ( C s ), , the A bands (a‘ ‘) are predicted to have a sharp medium Q branch with well-defined P and R envelopes, while the B and C bands (a‘) should exhibit hybrid contours with dominant character of either B or C . Indeed, the 3 1 and 4 1 components demonstrate C type prevalancy, the 7/2 1 B type and the 7/2 2 which is a combination of the stretch with the bend of a‘ ‘ is of A type.…”

“…An energy level diagram of possible perturbing states of a‘ symmetry that could be coupled via cubic or quartic terms to the 7/2 1 state of similar symmetry, within ±100 cm -1 is displayed in Figure . The energies of the possible perturbing states were obtained by calculating the values of the involved polyad components (based on the model of Dubal and Quack 18 ) and considering the energies of the other fundamental modes. , It is expected that these energies are somewhat higher than the energies of the perturbing states since the off-diagonal anharmonicities that are usually small and negative were not accounted for. As seen from Figure , almost all states are quite separated from the 7/2 1 state, except the 7/2 3 + ν 6 state which involves a higher polyad component, 7/2 3 , and the ν 6 ClCCl bend.…”

Controlling bond cleavage and probing intramolecular dynamics via photodissociation of rovibrationally excited molecules

“…The CHFCl 2 is an asymmetric top belonging to the C s point group for identical chlorine atoms and reduces to C 1 for di erent chlorine isotopes. In C s , the v 1 CH stretch and the v 2 CH bend are of a 0 and the v 7 CH bend of a 00 symmetry, while in C 1 the CH stretch and bends are of type a [123,124]. Owing to their symmetry, the observed bands are characterized by di erent shapes, where the 3 1 and 4 1 components demonstrate C type prevalancy, the 7/2 1 B type and the 7/2 2 , which is a combination of the stretch with the bend of a 00 is of A type (see ®gure 8).…”

Vibrational overtone spectra and vibrational dynamics of CFHCl2and (CH3)2CFH

“…CFHCI~ has been the subject of a VUV photolysis in matrix [15] and of the gas phase CO2-1aser photolysis [16]. Particularly helpful for us was a very recent analysis of the fundamental bands of CFHCI~ [17]. In contrast to this, only a few previous investigations have Downloaded by [Duke University Libraries] at 06:17 27 December 2014 appeared for CFH(CF~)z.…”