Rotationally resolved structures in the fifth and sixth torsional states of à [sup 1]A[sup ″] acetaldehyde: Internal rotation above the torsional barrier

Chou, Yung-Ching; Huang, Cheng-Liang; Chen, I-Chia; Ni, Chi-Kung; Kung, A. H.
November 2002
Journal of Chemical Physics;11/1/2002, Vol. 117 Issue 17, p7906
Academic Journal
The fluorescence excitation spectrum of acetaldehyde in its transition ùA'-&Xtilde;¹A' is analyzed for torsional states above the barrier. States with torsional vibrational quantum numbers v[sub t]=5A, 5E, and 6A at term energies 660-927 cm[sup -1] are assigned. This region is 100-370 cm[sup -1] above the torsional barrier. These states lie between the limits of torsional vibrational motion and free internal rotor motion, so that the close-lying 5A[sub 2] and 6A[sub 1] states mix for K>0, and K states in the E sublevel are widely split. From an analysis of calculated eigenfunctions, the composition of K=1 sublevels reaches nearly equal proportions of odd (A[sub 2]) and even (A[sub 1]) torsional wave functions when levels exceed the top of the torsional barrier, whereas the K=1 eigenfunctions of v[sub t]=4A[sub 1] lying near consists of mostly even (A[sub 1]) functions. Avoided crossings with ΔK=0 and Δm=0 mod 3 selection rules are observed between K=2, E sublevels of 14[sup 0+] 15[sup 4] and 14[sup 0+] 15[sup 5] and between K=2, E sublevels of 14[sup 0-] 15[sup 4] and 14[sup 0-]15[sup 5]. The K energy-level structure of 14[sup 0+] 15[sup 5] deviates significantly from the expected parabolic shape. The K structures and the K state at the lowest energy differ appreciably for the two inversion doublets 14[sup 0+] and 14[sup 0-].


Related Articles

  • Torsion-inversion coupling in the S1 state of acetaldehyde. Weersink, Robert A.; Cramb, David T.; Wallace, Stephen C.; Gordon, Robert D. // Journal of Chemical Physics;1/8/1995, Vol. 102 Issue 2, p623 

    Coupling between the methyl torsion (υ15) and inversion (υ14) modes is used to model the singlet π*←n spectrum of jet-cooled acetaldehyde and its deuterated analogs. The anomalies observed in the two torsion progressions built onto the lowest inversion doublet are accurately...

  • Effect of skeletal relaxation on the methyl torsion potential in acetaldehyde. Ozkabak, Ali G.; Goodman, Lionel // Journal of Chemical Physics;4/15/1992, Vol. 96 Issue 8, p5958 

    Fully-relaxed model ab initio calculations at Hartree–Fock/6–31G(d,p) and Mo\ller–Plesset (MP2)/6–31G(d,p) levels for acetaldehyde methyl conformers indicate significant skeletal flexing (e.g., the CH3 –C bond length changes by 0.006 Å) and methyl hydrogen...

  • On the physical interpretation of torsion-rotation parameters in methanol and acetaldehyde:... Li-Hong Xu; Lees, Ronald M.; Hougen, Jon T. // Journal of Chemical Physics;2/22/1999, Vol. 110 Issue 8, p3835 

    Studies equilibrium structural constants and torsion-rotation interaction parameters for methanol and acetaldehyde. Molecular flexing in the torsional potential barrier; Coefficients of torsion-rotation terns; Agreement between the Gaussian and global fit results for methanol and acetaldehyde.

  • Anomalous splittings of torsional sublevels induced by the aldehyde inversion motion in the S[sub 1] state of acetaldehyde. Chou, Yung-Ching; Chen, I-Chia; Hougen, Jon T. // Journal of Chemical Physics;2/1/2004, Vol. 120 Issue 5, p2255 

    The G[sub 6] group-theoretical high-barrier formalism developed previously for internally rotating and inverting CH[sub 3]NHD is used to interpret the abnormal torsional splittings in the S[sub 1] state of acetaldehyde for levels 14[sup 0-]15[sup 0], 14[sup 0-]15[sup 1], and 14[sup 0-]15[sup 2],...

  • PO-RR-073-SA.  // Physical Therapy;May1998, Vol. 78 Issue 5, pS26 

    Presents a summary of an article entitled `Comparison of Lateral Tibial Torsion in Females Trained in Classical Ballet and Females With No Classical Ballet Training,' by M.A. Watson and B.S. Smith.

  • Torsion boot needs second look.  // PS: Preventive Maintenance Monthly;Jul98, Issue 548, p25 

    Provides information about the maintenance of driveshaft's torsion boot. Factors that can cause the boot to weaken; How to avoid transmission failure.

  • Nicotine psychopharmacology research: advancing science, public health, and global policy. Henningfield, Jack E.; Stolerman, Ian P.; Miczek, Klaus A. // Psychopharmacology;Feb2006, Vol. 184 Issue 3/4, p263 

    The article discusses various reports published within the issue, including one by Victor De Noble and Paul Mele on interactions among nicotine and other substances including acetaldehyde and mecamylamine.

  • Effects of acetaldehyde on cell regeneration and differentiation of the upper gastrointestinal... Homann, Nils; Karkkainen, Paivi // JNCI: Journal of the National Cancer Institute;11/19/97, Vol. 89 Issue 22, p1692 

    Investigates the effects of acetaldehyde on cell regeneration and differentiation of the upper gastrointestinal tract. Greater cell proliferation caused by acetaldehyde; Production of acetaldehyde after alcohol consumption; Thicker epithelia caused by acetaldehyde; Possible explanation given by...

  • Acetaldehyde photochemistry: The radical and molecular dissociations. Yadav, Janardan S.; Goddard, John D. // Journal of Chemical Physics;3/1/1986, Vol. 84 Issue 5, p2682 

    The dissociation of acetaldehyde to radical products, CH3+HCO and H+CH3CO, and to the molecular limit of CH4+CO has been investigated by ab initio SCF calculations. Effects of zero point energy corrections and of electron correlation on energy differences have also been considered. The computed...


Read the Article


Sorry, but this item is not currently available from your library.

Try another library?
Sign out of this library

Other Topics