High resolution FTIR spectroscopy of pentafluoroethane: perturbations in the Coriolis doublet of ν4 and ν13

The high-resolution, jet-cooled infrared spectrum of pentafluoroethane

“…With a rotational temperature of about 10 K, the maximum quantum numbers observed in our data were J 0 = 21 and K 0 a ¼ 14. This is significantly different from the data of McNaughton et al [12] and Thompson et al [13] using enclosive flow cooling, i.e. J 0 = 86 and K 0 a ¼ 50 for the m 4 .…”

“…In a separate paper [13], has three avoided level crossings, near K a = 7, K a = 38, and K c = 39. Several different approaches were tried, but they were unable to obtain an acceptable fit due to an apparent c-axis perturbation from a dark state at higher energy.…”

“…This region includes the m 3 , m 4 , and m 13 studied by previous workers [12,13], as well as the m 5 and m 14 where rotational assignments have not previously been reported. The extremely cold rotational temperature of this spectrum means that there is limited overlap between the rotational assignments in the m 4 and m 13 made by Thompson et al [13] and those of this work. It also means that the overlapping m 5 and m 14 have been assigned for the first time.…”

“…They determined the rotational and quartic centrifugal distortion constants for all of the states except m 18 = 5. The microwave spectra of CF 3 CHF 2 , 13 CF 3 CHF 2 , CF 3 13 CHF 2 were recorded by Onda et al [4] who determined the r s (C-C) bond length.…”

High-resolution infrared study of collisionally cooled trans-1,2-dichloroethylene

“…[1]. The method has proven valuable for high-resolution infrared studies of several fluorocarbons and chlorofluorocarbons [2][3][4][5][6][7][8]. In the present work the new apparatus is demonstrated in an infrared study of natural isotopic trans-1,2-dichloroethylene (tDCE).…”