title: Microwave, high-resolution infrared, and quantum chemical investigations of CHBrF2: ground and v4 = 1 states.
abstract: A combined microwave, infrared, and computational investigation of CHBrF(2) is reported. For the vibrational ground state, measurements in the millimeter- and sub-millimeter-wave regions for CH(79)BrF(2) and CH(81)BrF(2) provided rotational and centrifugal-distortion constants up to the sextic terms as well as the hyperfine parameters (quadrupole-coupling and spin-rotation interaction constants) of the bromine nucleus. The determination of the latter was made possible by recording of spectra at sub-Doppler resolution, achieved by means of the Lamb-dip technique, and supporting the spectra analysis by high-level quantum chemical calculations at the coupled-cluster level. In this context, the importance of relativistic effects, which are of the order of 6.5% and included in the present work using second-order direct perturbation theory, needs to be emphasized for accurate predictions of the bromine quadrupole-coupling constants. The infrared measurements focused on the ν(4) fundamental band of CH(79)BrF(2). Fourier transform investigations using a synchrotron radiation source provided the necessary resolution for the observation and analysis of the rotational structure. The spectroscopic parameters of the v(4) = 1 state were found to be close to those of the vibrational ground state, indicating that the ν(4) band is essentially unaffected by perturbations.
authors.affiliation: Dipartimento di Chimica G. Ciamician, Università di Bologna, Via F. Selmi 2, I-40126 Bologna, Italy.
authors.forename: Gabriele
authors.initials: G
authors.lastname: Cazzoli
authors.forename: Lino
authors.initials: L
authors.lastname: Cludi
authors.forename: Cristina
authors.initials: C
authors.lastname: Puzzarini
authors.forename: Paolo
authors.initials: P
authors.lastname: Stoppa
authors.forename: Andrea
authors.initials: A
authors.lastname: Pietropolli Charmet
authors.forename: Nicola
authors.initials: N
authors.lastname: Tasinato
authors.forename: Agostino
authors.initials: A
authors.lastname: Baldacci
authors.forename: Alessandro
authors.initials: A
authors.lastname: Baldan
authors.forename: Santi
authors.initials: S
authors.lastname: Giorgianni
authors.forename: René
authors.initials: R
authors.lastname: Wugt Larsen
authors.forename: Stella
authors.initials: S
authors.lastname: Stopkowicz
authors.forename: Jürgen
authors.initials: J
authors.lastname: Gauss