Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
9589523 | Journal of Molecular Spectroscopy | 2005 | 6 Pages |
Abstract
The FTIR spectrum of pentafluoroethane (R125) was measured in the mid infrared region from 900 to 4000 cmâ1. Vibrational assignments for R125 are revised by comparison of previous and current experimental data with ab initio calculations at both the MP2/6-311+(d,p) and B3LYP/TZV+(3df,3p) levels of theory. High resolution FTIR spectra were recorded at room temperature and in an enclosive flow cell at a rotational temperature of 140 K. The cold spectrum was sufficiently resolved to enable rovibrational analyses of the overlapping ν4 (1200.7341 cmâ1) and ν13 (1223.3 cmâ1) bands, which have a/c hybrid and b-type character, respectively. Ground state combination differences were used to confirm assignment of 2375 lines to ν4 (Jmax = 86, Ka max = 50) and 2921 lines to ν13 (Jmax = 60, Ka max = 54). Effective rotational and centrifugal distortion constants were determined for ν4, and the polarization ratio was found to be Îμa2/Îμc2=1.0:1.1. Severe Coriolis perturbations prevent any satisfactory fit to the ν13 band.
Related Topics
Physical Sciences and Engineering
Chemistry
Physical and Theoretical Chemistry
Authors
Christopher D. Thompson, Evan G. Robertson, Ivana Aleksic, Don McNaughton,