title: Microwave Spectra, Structure, and Ring-Puckering Vibration of Octafluorocyclopentene.
abstract: The rotational spectra of octafluorocyclopentene (C5F8) has been measured for the first time using pulsed jet Fourier transform microwave spectroscopy in a frequency range of 6 to 16 GHz. As in the molecule cyclopentene, the carbon ring is nonplanar, and inversion through the plane results in an inversion pair of ground state vibrational energy levels with an inversion splitting of 18.4 MHz. This large amplitude motion leads to the vibration-rotation coupling of energy levels. The symmetric double minimum ring-puckering potential function was calculated, resulting in a barrier of 222 cm-1. The rotational constants A0= 962.9590(1) MHz, B0= 885.1643(4) MHz, C0= 616.9523(4) MHz, A1= 962.9590(1) MHz, B1= 885.1643(4) MHz, C1= 616.9528(4) MHz, and two centrifugal distortion constants for each state were determined for the parent species and all13C isotopologues. A mixed coordinate molecular structure was determined from a least-squares fit of the ground state rotational constants of the parent and each13C isotopologue combined with the equilibrium bond lengths and angles from quantum chemical calculations.
authors.affiliation: Department of Chemistry, Wesleyan University , Hall-Atwater Laboratories, 52 Lawn Avenue, Middletown, Connecticut 06459, United States.
authors.forename: B E
authors.initials: BE
authors.lastname: Long
authors.affiliation: Department of Chemistry, Wesleyan University , Hall-Atwater Laboratories, 52 Lawn Avenue, Middletown, Connecticut 06459, United States.
authors.forename: Eric A
authors.initials: EA
authors.lastname: Arsenault
authors.affiliation: Department of Chemistry, Wesleyan University , Hall-Atwater Laboratories, 52 Lawn Avenue, Middletown, Connecticut 06459, United States.
authors.forename: Daniel A
authors.initials: DA
authors.lastname: Obenchain
authors.affiliation: School of Natural and Social Sciences, Purchase College SUNY , 735 Anderson Hill Road, Purchase, New York 10577, United States.
authors.forename: Yoon Jeong
authors.initials: YJ
authors.lastname: Choi
authors.affiliation: Department of Chemistry, Texas A & M University , College Station, Texas 77840, United States.
authors.forename: Esther J
authors.initials: EJ
authors.lastname: Ocola
authors.affiliation: Department of Chemistry, Texas A & M University , College Station, Texas 77840, United States.
authors.forename: Jaan
authors.initials: J
authors.lastname: Laane
authors.affiliation: Department of Chemistry, Wesleyan University , Hall-Atwater Laboratories, 52 Lawn Avenue, Middletown, Connecticut 06459, United States.
authors.forename: Wallace C
authors.initials: WC
authors.lastname: Pringle
authors.affiliation: School of Natural and Social Sciences, Purchase College SUNY , 735 Anderson Hill Road, Purchase, New York 10577, United States.
authors.forename: S A
authors.initials: SA
authors.lastname: Cooke