Vibrational spectra of tetrafluoroethylene and tetrachloroethylene

Abstract

Th e infrared spectra of gaseous tet raftu oroethylene from 22 to 52 j1. and liquid tetrachloroeth ylene from 3 to 52 j1. have been determined. Several hitherto unobserved bands were found. N ew and sati sfactory assignments, for which a detailed discuss ion is given, have bee n achieved. Th e ou t-of-plane forc e co nstants are di scussed and u sed to predict the wagging and torsion frequ encies of tet rabromoeth ylene. Tables of the therm odynamic fun ctions for tetrafluoro-and tetrach loroethy lene are prese nted .

Structural, vibrational, and rovibrational analysis of tetrafluoroethylene

“…A value was derived for the torsional vibration (ν 4 ), which is neither IR nor Raman active and was previously only estimated from thermodynamic data. 4 A much better contour than previously reported 4 was measured for the lowest-wavenumber IR active band (ν 10 ) and its band origin (confirmed by a combination band); whereas the band origin is near the minimum of this contour, a satellite maximum at 195 cm −1 might be due to a Coriolis resonance with ν 4 , transferring some intensity to this torsional vibration as suggested already in Ref. 4 and further supported by the high calculated coupling constant reported by Castro.…”

“…1 Vibrational assignments of 12 C 2 F 4 date back to an infrared study in 1945 2 and a combined IR and Raman study in 1950; 3 the lowestwavenumber IR active band was measured in 1954 and the IR and Raman inactive torsion vibration estimated from thermodynamic data. 4 These assignments were summarised by Shimanouchi. 5 In earlier work by Robertson et al 6 using a sample with natural isotopic abundance cooled to 160 K, high resolution spectra of the intense symmetric (ν 11 ) and antisymmetric (ν 9 ) CF 2 stretches in the mid-infrared region were measured.…”

The electron affinities of the perfluorocarbons C2Fn, n=1–6

“…The geometry of C 2 F 4 has been determined by electron diffraction 31 and the BH-LYP method is within 0.006 Å of each of the two experimental bond lengths, while the other DFT methods predict longer bond lengths by a few hundredths of an Å ngstrom. The experimental vibrational frequencies given in Table IX are those selected by Shimanouchi 32 from the data of Mann, 33 Monfils, 34 and Nielsen. 35 Two low-energy minima found for C 2 F 4 Ϫ are given in Fig.…”

Thermal Plasma Decomposition of Tetrachloroethylene

“…The band origins are obtained by theoretical analysis and take place at 1594.6 (ν 2 ), 3656.7 (ν 1 ) and 3755.8 (ν 3 ) cm -1 and also as a weak overtone at 3154.4 (2ν 2 ) cm -1 (Run-7).Two other compounds were also detected, but their intensities were weak and therefore their concentrations could not have been calculated. Two bands of C 2 Cl 4 were shown in the spectrum of Run-2 at 795 (ν 11 ) and 918.6 (ν 9 ) cm -1 , which belongs to the stretching of C-Cl[29]. In Run-13 the band of ONCl was observed at 595.8 (ν 2 ), 1799 (ν 1 ) and 2131 (ν 1+ ν 3 ) cm -1[30].…”