Vibrational spectrum of perfluoroethane

Fermi resonances in the vibrational spectrum of perfluoroethane

“…Such threefold resonances were discussed in more detail in [11]. The paper [11] shows that a threefold resonance appears in the form of a doublet in the case where the interaction matrix elements are larger than the splitting of unperturbed levels E 2 (m 6 + m 11 ) and E 3 (2m 8 ).…”

“…4). Notes: 1 -the authors of [7] interpreted this band as (2m 8 , E g ), 2 -the authors of [7] interpreted this band as (m 2 + m 8 , E g ). Table 3 presents the results of processing of the experimental data obtained from the Raman spectrum of liquid C 2 F 6 and IR spectra C 2 F 6 in liquid N 2 and in liquid Xe [8] …”

“…The sample temperature is controlled both by nitrogen entering the nitrogen chamber (7) and a heating spiral (8). The temperature is measured by a thermocouple (9).…”

“…However, the presence of Fermi resonances of states m 1 $ 2m 6 (A 1g ) and m 7 $ 2m 8 $ m 6 + m 11 (E g ) was recently predicted in paper [8]. According to [8], doublets and more complicated structures are observed in the IR spectrum of solution of C 2 F 6 in Xe (T = 163 K) in the spectral regions corresponding to vibrations combined with m 1 and m 7 , which can only be interpreted with the resonance interactions taken into account. Therefore one can expect Fermi resonance multiplets m 1 $ 2m 6 (A 1g ) and m 7 $ 2m 8 $ m 6 + m 11 (E g ) to appear in the Raman spectrum of C 2 F 6 molecule.…”

“…The goals of this work are to measure the Raman frequencies in the spectrum of liquid C 2 F 6 more accurately, to determine their relative intensities, and to specify resonance characteristics of higher vibrational states using the IR spectrum of C 2 F 6 in liquid N 2 and compare them with the spectrum of C 2 F 6 in liquid Xe [8].…”