PAPE band (nu(6)+nu(8))(0) and the hot bands nu(6)+nu(8)-nu(8) of CD3CN

Citation
R. Anttila et al., PAPE band (nu(6)+nu(8))(0) and the hot bands nu(6)+nu(8)-nu(8) of CD3CN, J MOL STRUC, 517, 2000, pp. 133-143
Citations number
19
Categorie Soggetti
Physical Chemistry/Chemical Physics
Journal title
JOURNAL OF MOLECULAR STRUCTURE
ISSN journal
00222860 → ACNP
Volume
517
Year of publication
2000
Pages
133 - 143
Database
ISI
SICI code
0022-2860(20000216)517:<133:PB(ATH>2.0.ZU;2-1
Abstract
The infrared spectrum of CD3CN around 1380 cm(-1) has been studied at a res olution of 0.0040 cm(-1). in this region the combination of two perpendicul ar fundamentals nu(6) and nu(8) is located. In the spectrum only the parall el component was observed although the path length was 150 m and the pressu re 70 Pa. In this PAPE type band 1340 lines were assigned in 17 sub-bands. The vibrational e-doubling and -resonance together with strong effects of r otational l-resonances with the perpendicular component of the same vibrati onal level were observed. In addition, the Coriolis resonance with nu(3) nu(8) and certain anharmonic perturbations complicated the analysis. To cre ate a better model both the hot bands (nu(6) + nu(8))(0) - nu(8) and (nu(6) + nu(8))(2) - nu(8) were assigned (1508 lines) and analyzed together with the PAPE band. In the hot band (nu(6) + nu(8))(0) - nu(8) the Q branch (P)Q (1) around 1049.5 cm(-1) was found to have a doublet structure and the spli tting in the sub-band gave direct information about the vibrational e-doubl ing. The splitting of K Delta K = 1 sub-band in (nu(6) + nu(8))(2) - nu(8) giving rise to two families of lines was detected, too. In the calculations attention was paid to the main features of the PAPE problem, Higher order fitting parameters were avoided to keep the results reliable. The standard deviation 2.7 x 10(-3) cm(-1) may be considered satisfactory, when taking i nto account the complexity of the whole system. (C) 2000 Elsevier Science B .V. All rights reserved.