High resolution Fourier transform infrared spectra and analysis of the ν_(14), ν_(15) and ν_(16) bands of azetidine

摘要

Rotationally resolved vibrational spectra of the three lowest frequency bands of the four-membered heterocycle azetidine (c-C_3H _6NH) have been collected with a resolution of 0.00096 cm~(-1) using the far infrared beamline at the Canadian Light Source synchrotron. The modes observed correspond principally to motions best described as: β-CH_2 rock (ν_(14)) at 736.701310(7) cm~(-1), ring deformation (ν_(15)) at 648.116041(8) cm~(-1), and the ring puckering mode (ν_(16)) at 207.727053(9) cm~(-1). A global fit of 14 276 rovibrational transitions from the three bands provided an accurate set of ground state spectroscopic constants as well as excited state parameters for each of the three vibrational modes. The ground state structure was determined to be that of the puckered conformer having the NH bond in an equatorial arrangement.