Far-Infrared Spectra of Trimethylene Sulfide and Cyclobutanone

Abstract

The far-infrared spectra of trimethylene sulfide and cyclobutanone have been investigated. The positions of the trimethylene sulfide bands observed are well fitted by the potential function derived from the microwave studies of Harris et al. However, some of the band shapes cannot be explained in detail although the anomalies are probably due to Coriolis terms in the Hamiltonian. The positions of the lower frequency bands of cyclobutanone can be fit approximately by a quartic—quadratic potential with a small barrier. Although this potential function fits the rotational constants measured by Sharpen et al., it does not predict the positions of the higher frequency bands correctly. Furthermore the band shapes cannot be explained on the basis of the simple potential function, and it is suggested that the low-frequency out-of-plane vibration of cyclobutanone is perturbed by a higher frequency vibration.

Coherent Motion Reveals Non‐Ergodic Nature of Internal Conversion between Excited States

“…The period of oscillation corresponds to a vibrational frequency of~35 cm À1 . Far-infrared studies have revealed a vibration of frequency~36.5 cm À1 corresponding to a ring-puckering mode in the ground state of cyclobutanone which could be a candidate for this, [31] and this mode would thus have a very similar vibrational period in the 3s state.…”

Cycloalka(alke) Nones as Structural Fragments in Liquid Crystals

“…It has been demonstrated that the cyclobutanone is floppy molecule (compare with puckered, nonplanar parent cyclobutane) [7]. Its slightly distorted chair conformation is a little bit higher in energy than the parent system [8,9]. According to Tamagawa and Hilderbrandt [10], slightly distorted cyclopentanone can either be twisted, with C 2 symmetry, or it can be bent, with C s symmetry.…”

New laboratory techniques using heterodyne receivers

“…Cyclobutanone (C 4 H 6 0) shows a vibrational band (ν 2←3 ) at 65 cm −1 (1.95 THz) (Borgers & Strauss (1966)). Calculated IR intensities on a B3LYP/aug-cc-pVDZ level are on the order of 13.4 km/mole.…”