Microwave spectral study of 2-fluorobenzonitrile

Centrifugal distortion analysis of the millimeter-wave spectrum of 2-fluorobenzonitrile and ab initio DFT calculations

“…First of all, a-type R-branch transitions of some low to moderately high J and K À1 values were predicted using the rotational constants reported in [1,2]. The low K À1 lines that were found very close to the predicted frequencies were measured and included in the fit with previously reported lines [2]. Gradually, higher J and K À1 transitions including some b-type R-branch, were predicted and identified by the ''bootstrap'' method reported by Kirchhoff [6].…”

“…A maximum CD contribution of À17.9 MHz was noticed for 37(18,19) ‹ 36(18,18) transition. Finally, 138 newly measured and 22 previously reported [2] transition frequencies were fit to the semi rigid rotor Watson's A and S-reduction Hamiltonian in the I r representation [7]. All 160 transitions used in the least-squares analysis have been submitted as a supplementary material.…”

“…This was due to the fact that high J and K À1 transitions were not assigned in this work. Later on, Dutta et al [2] have investigated the ground state rotational spectra in the frequency range 12.5-18.0 and 22.0-26.0 GHz using radio-frequency microwave double resonance (RFMWDR) technique [3]. From a least-square analysis of the assigned transitions they have determined the three rotational constants and proposed an r o -structure, which reproduced the observed principal moments of inertia values quite well.…”

Orientational order of planar solutes in a zero average electric field gradient nematic environment

“…The orientational order matrix was obtained from the dipolar coupling constants in Tables 1-3 using the least squares program Shape [27] and hexagonal structures for all solutes, except for 2-and 3-fluorobenzonitrile where the microwave structures [28,29] were used. The geometrical parameters employed are given in table 4.…”

Assignment and analysis of the rotational spectrum of 3-chlorobenzonitrile

“…The spectroscopic properties of these molecules are dominated by those of the nitrile group, and changing the position of the halogen leads to useful information on the evolution of such properties relative to those of benzonitrile. Analysis of the microwave spectra of 2-fluoro [1][2][3], 3-fluoro [4,3], and 4-fluorobenzonitrile [5,6,3] facilitated, in particular, a useful comparison of nuclear quadrupole coupling between benzonitrile and the three fluorobenzonitrile molecules [3]. The rotational spectra of 2-chloro [7] and 4-chlorobenzonitrile [8] have also been studied, although the acquired data were satisfactorily described by rigid rotor analysis, while analysis of nuclear quadrupole coupling was limited to rudimentary information on the chlorine nucleus.…”