The CH stretching first overtone triad of ketene

✍ Scribed by Brent Strickler; László Nemes; Martin Gruebele

• Book ID: 104151811
• Publisher: Elsevier Science
• Year: 2003
• Tongue: English
• Weight: 200 KB
• Volume: 219
• Category: Article
• ISSN: 0022-2852
• DOI: 10.1016/s0022-2852(03)00092-4

✦ Synopsis

We have observed and analyzed the first overtone triad of the m 1 and m 7 CH stretching modes of ketene in the range of 6000-6300 cm À1 . The K a ¼ 0 components of all three bands could be assigned based on missing Q-branches and combination differences, allowing an unambiguous determination of the rotationless band origins for the 2m 1 , m 1 þ m 7 , and 2m 7 bands. In addition, the K a ¼ 1; 2, and 3 subbranches as well as some higher K a stacks were assigned for all three bands. The 2m 7 band suffers from the most serious Coriolis perturbations, while at least some subbranches of the other bands could be fitted together. The anharmonic coupling structure perturbing the CH stretching overtones is discussed in terms of a quartic anharmonic force field derived from eight pair GVB/RCI calculations. Finally, an assignment of the K a ¼ 1 and K a ¼ 3 subbands of the 2m 2 CO stretching overtone is also presented, together with an estimate of the rotationless band origin. A coincidence of several subbands prevented the unambiguous assignment of the K a ¼ 0 stack in this case.