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Internal dynamics in the molecular complex of CF3CN and H2O
Get PDFThe rotational spectrum of trifluoroacetonitrile–water complex has been studied by pulsed-nozzle, Fourier transform microwave spectroscopy. Both a-type and b-type transitions have been observed. The rotational constants, centrifugal distortion constants, and the 14N nuclear quadrupole coupling constants have been determined. The complex is T-shaped, with the oxygen atom from the water located 3.135 Å from the carbon atom of CF3 of the trifluoroacetonitrile molecule
The Rotational Spectrum of Perfluoropropionic Acid
No full textThe pure rotational spectrum of perfluoropropionic acid, CF 3CF 2COOH, has been studied by a pulsed nozzle, chirped-pulse Fourier transform microwave spectrometer in the frequency range of 8-14 GHz. a total of 81 transitions, including a-type, b-type, and c-type transitions have been observed and analyzed. the rotational constants and the five quartic centrifugal distortion constants were determined for the first time. the rotational constants are a = 1893.5299(4) MHz, B = 1175.7031(4) MHz, and C = 1118.2017(5) MHz. Quantum chemical calculations and the spectral analysis indicate that the observed conformer is the gauche form of perfluoropropionic acid with calculated dihedral angles ∠CCCO = 106° and 107° from MP2/6-311G++(3df, 3pd) and MP2/Aug-CC-pVDZ calculations, respectively. the experimental spectroscopic constants are compared to those obtained from ab initio calculations
The Pure Rotational Spectrum of a Claisen Rearrangement Precursor Allyl Phenyl Ether using CP-FTMW Spectroscopy
No full textThe pure rotational spectrum of a Claisen rearrangement precursor, Allyl Phenyl Ether (APE), has been measured on a chirped pulse Fourier transform microwave (CP-FTMW) spectrometer in the 8-14 GHz region. Rotational and centrifugal distortion constants for multiple conformations have been determined and are reported for the first time. This is the first study of a phenyl-containing ether where multiple conformers were experimentally observed all within their ground vibrational states. Quantum chemical calculations have been performed to isolate low energy geometries of APE and are implemented to aid in spectral assignment. Other structural parameters such as planar moments and inertial defects for the Allyl Phenyl Ether conformers are presented and compared to similar molecules
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
The position of deuterium in HOD—NNO as determined by structural and nuclear quadrupole coupling constants
No full textRotational spectra of the weakly bound H2O-N2O complex and its HOD-N2O isotopologue in a supersonic jet are reported. Rotational constants of the singly substituted deuterium in water and each singly substituted nitrogen-15 are presented. Combinations of isotopic data and high level ab initio calculations place the water in a similar position to those of the isoelectronic H2O-CO2 complex, with a slight tilt of the OH towards the NNO axis. The deuterium nuclear quadrupole coupling constant places the deuterium on the O-H axis quasi-parallel to the NNO axis
H₂ - AgCl: A Spectroscopic Study of a Dihydrogen Complex
No full textH2-AgCl has been observed on a Fourier transform microwave spectrometer equipped with laser ablation source and determined to be a dihydrogen complex. Transitions up to J = 3-2 have been measured and analyzed for four isotopologues of the complex containing ortho and para H2. the ortho and para spin states have been included in one fit, a deviation from the typical H2 complex. Rotational constants B and C, centrifugal distortion constants ΔJ and ΔJK, nuclear electric quadrupole coupling constants χaa, χbb, and χcc for 35Cl and 37Cl have been fit for both spin states while nuclear spin-nuclear spin constants D aa , D bb, and D cc, and nuclear spin-rotation constant Caa have been reported for the ortho spin state. Quantum chemical calculations predict a strong bonding interaction and the strength of the complex has been related to reported χaa and ΔJ values amongst a host of comparable species, including the AgCl monomer itself. Bond lengths have been determined for Ag-Cl, Ag-H2 center-of-mass, and H-H and are reported
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