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Full-Text Articles in Physical Sciences and Mathematics
Infrared Spectra Of The Li +_(H 2)N(N=1-3) Cation Complexes, C Emmeluth, B L. J Poad, C D. Thompson, G H. Weddle, E J. Bieske
Infrared Spectra Of The Li +_(H 2)N(N=1-3) Cation Complexes, C Emmeluth, B L. J Poad, C D. Thompson, G H. Weddle, E J. Bieske
Berwyck L. J. Poad
The Li+–(H2)n n = 1–3 complexes are investigated through infrared spectra recorded in the H–H stretch region (3980–4120 cm−1) and through ab initio calculations at the MP2∕aug-cc-pVQZ level. The rotationally resolved H–H stretch band of Li+–H2 is centered at 4053.4 cm−1 [a −108 cm−1 shift from the Q1(0) transition of H2]. The spectrum exhibits rotational substructure consistent with the complex possessing a T-shaped equilibrium geometry, with the Li+ ion attached to a slightly perturbed H2 molecule. Around 100 rovibrational transitions belonging to parallel Ka = 0‐0, 1-1, 2-2, and 3-3 subbands are observed. The Ka = 0‐0 and 1-1 transitions …
Attachment Of Molecular Hydrogen To An Isolated Boron Cation: An Infrared And Ab Initio Study, Viktoras Dryza, Berwyck L. J Poad, Evan J. Bieske
Attachment Of Molecular Hydrogen To An Isolated Boron Cation: An Infrared And Ab Initio Study, Viktoras Dryza, Berwyck L. J Poad, Evan J. Bieske
Berwyck L. J. Poad
Structural properties of the B+−H2 electrostatic complex are investigated through its rotationally resolved infrared spectrum in the H−H stretch region (3905−3975 cm−1). The spectrum, which was obtained by monitoring B+ photofragments while the IR wavelength was scanned, is consistent with the complex having a T-shaped structure and a vibrationally averaged intermolecular separation of 2.26 Å, which decreases by 0.04 Å when the H2 subunit is vibrationally excited. The H−H stretch transition of B+−H2 is red-shifted by 220.6 ± 1.5 cm−1 from that of the free H2 molecule, much more than for other dihydrogen complexes with comparable binding energies. Properties of …
Interactions Between The Chloride Anion And Aromatic Molecules: Infrared Spectra Of The Cl-_C6h5ch3, Cl-_C6h5nh2 And Cl-_C6h5oh Complexes, Corinna Emmeluth, Berwyck L. J Poad, Christopher D. Thompson, Evan J. Bieske
Interactions Between The Chloride Anion And Aromatic Molecules: Infrared Spectra Of The Cl-_C6h5ch3, Cl-_C6h5nh2 And Cl-_C6h5oh Complexes, Corinna Emmeluth, Berwyck L. J Poad, Christopher D. Thompson, Evan J. Bieske
Berwyck L. J. Poad
The Cl-−C6H5CH3·Ar, Cl-−C6H5NH2·Ar, and Cl-−C6H5OH·Ar anion complexes are investigated using infrared photodissociation spectroscopy and ab initio calculations at the MP2/aug-cc-pVDZ level. The results indicate that for Cl-−C6H5NH2 and Cl-−C6H5OH, the Cl- anion is attached to the substituent group by a single near-linear hydrogen bond. For Cl-−C6H5CH3, the Cl- is attached to an ortho-hydrogen atom on the aromatic ring and to a hydrogen atom on the methyl group by a weaker hydrogen bond. The principal spectroscopic consequence of the hydrogen-bonding interaction in the three complexes is a red-shift and intensity increase for the CH, NH, and OH stretching modes. Complexities in …
Infrared Spectra Of Mass-Selected Al+_(Ch4)Nn=1-6clusters, B Poad, C Thompson, E Bieske
Infrared Spectra Of Mass-Selected Al+_(Ch4)Nn=1-6clusters, B Poad, C Thompson, E Bieske
Berwyck L. J. Poad
Infrared spectra are recorded for Al+–(CH4)n n = 1–6 clusters in the CH stretch region (2800–3100 cm−1). The spectra, which are obtained by monitoring photofragmentation in a tandem mass spectrometer, are dominated by a single, narrow band corresponding to the totally symmetric C–H stretching mode of the CH4 subunits (rendered infrared active through the interaction with the Al+ cation). This band shifts progressively to higher wavenumber as the clusters becomes larger, concomitant with a weakening of the intermolecular Al+⋯CH4 bonds. Supporting ab initio calculations for the n = …
Rotationally Resolved Infrared Spectrum Of The Li+_D2 Cation Complex, C D. Thompson, C Emmeluth, B L. J Poad, G H. Weddle, E J. Bieske
Rotationally Resolved Infrared Spectrum Of The Li+_D2 Cation Complex, C D. Thompson, C Emmeluth, B L. J Poad, G H. Weddle, E J. Bieske
Berwyck L. J. Poad
The infrared spectrum of mass selected Li +-D 2 cations is recorded in the D-D stretch region (2860-2950 cm -1) in a tandem mass spectrometer by monitoring Li + photofragments. The D-D stretch vibration of Li +-D 2 is shifted by -79 cm -1 from that of the free D 2 molecule indicating that the vibrational excitation of the D 2 subunit strengthens the effective Li +-D 2 intermolecular interaction. Around 100 rovibrational transitions, belonging to parallel K a=0-0, 1-1, and 2-2 subbands, are fitted to a Watson A-reduced Hamiltonian to yield effective molecular parameters. The infrared spectrum shows that …
Mixing Laser Spectroscopy And Mass Spectrometry- Infrared Spectra Of Metal Cation- Hydrogen Complexes, Vikoras Dryza, Berwyck Poad, Evan Bieske
Mixing Laser Spectroscopy And Mass Spectrometry- Infrared Spectra Of Metal Cation- Hydrogen Complexes, Vikoras Dryza, Berwyck Poad, Evan Bieske
Berwyck L. J. Poad
We describe recent experiments in which mass spectrometry and laser spectroscopy are combined to characterize Li(+)-H(2), Na(+)-H(2), B(+)-H(2), and Al(+)-H(2) complexes in the gas-phase. The infrared spectra, which feature full resolution of rotational sub-structure, are recorded by monitoring M(+) photo fragments as the infrared wavelength is scanned. The spectra deliver detailed information on the way in which a hydrogen molecule is attached to a metal cation including the intermolecular separation, the force constant for the intermolecular bond and the H-H stretching frequency. The complexes all possess T-shaped equilibrium geometries and display a clear correlation between the length and force constant …
Attaching Molecular Hydrogen To Metal Cations: Perspectives From Gas-Phase Infrared Spectroscopy, Viktoras Dryza, Berwyck Poad, Evan Bieske
Attaching Molecular Hydrogen To Metal Cations: Perspectives From Gas-Phase Infrared Spectroscopy, Viktoras Dryza, Berwyck Poad, Evan Bieske
Berwyck L. J. Poad
In this perspective article we describe recent infrared spectroscopic investigations of mass-selected M+–H2 and M+–D2 complexes in the gas-phase, with targets that include Li+–H2, B+–H2, Na+–H2, Mg+–H2, Al+–H2, Cr+–D2, Mn+–H2, Zn+–D2 and Ag+–H2. Interactions between molecular hydrogen and metal cations play a key role in several contexts, including in the storage of molecular hydrogen in zeolites, metal–organic frameworks, and …
Rotationally Resolved Infrared Spectrum Of The Na+-D2 Complex: An Experimental And Theoretical Study, Berwyck L. Poad, V Dryza, J Klos, A A. Buchachenko, E J. Bieske
Rotationally Resolved Infrared Spectrum Of The Na+-D2 Complex: An Experimental And Theoretical Study, Berwyck L. Poad, V Dryza, J Klos, A A. Buchachenko, E J. Bieske
Berwyck L. J. Poad
The infrared spectrum of mass-selected Na+-D2 complexes is recorded in the D-D stretch vibration region (2915-2972 cm−1) by detecting Na+ photofragments resulting from photo-excitation of the complexes. Analysis of the rotationally resolved spectrum confirms a T-shaped equilibrium geometry for the complex and a vibrationally averaged intermolecular bond length of 2.461 Å. The D-D stretch band centre occurs at 2944.04 cm−1, representing a −49.6 cm−1 shift from the Q1(0) transition of the free D2 molecule. Variational rovibrational energy level calculations are performed for Na+-D2 utilising an ab initio potential energy surface developed previously for investigating the Na+-H2 complex [B. L. J. …
Infrared Spectra Of Cl-_(C6h6)Mm=1, 2, Christopher Thompson, Berwyck Poad, Corinna Emmeluth, Evan Bieske
Infrared Spectra Of Cl-_(C6h6)Mm=1, 2, Christopher Thompson, Berwyck Poad, Corinna Emmeluth, Evan Bieske
Berwyck L. J. Poad
The Cl--(C6H6)Arn n = 0,1,2 and Cl--(C6H6)2 complexes are investigated using photodissociation infrared spectroscopy in the CH stretch region and through ab initio calculations at the MP2/aug-cc-pVDZ level. The results indicate that Cl--C6H6 possesses a planar structure in which the benzene molecule is attached to the Cl- anion by a double hydrogen bond. The calculations predict that Cl (C6H6)2 has a C2 symmetry structure in which the two face-to-face benzene molecules are attached to …
Infrared Spectra Of Mass-Selected Mg+-H2 And Mg +-D2 Complexes, Viktoras Dryza, Berwyck L. Poad, Evan J. Bieske
Infrared Spectra Of Mass-Selected Mg+-H2 And Mg +-D2 Complexes, Viktoras Dryza, Berwyck L. Poad, Evan J. Bieske
Berwyck L. J. Poad
Rotationally resolved infrared spectra of Mg(+)-H(2) and Mg(+)-D(2) are recorded in the H-H (4025-4080 cm(-1)) and D-D (2895-2945 cm(-1)) stretch regions by monitoring Mg(+) photofragments. The nu(HH) and nu(DD) transitions of Mg(+)-H(2) and Mg(+)-D(2) are red-shifted by 106.2 +/- 1.5 and 76.0 +/- 0.1 cm(-1) respectively from the fundamental vibrational transitions of the free H(2) and D(2) molecules. The spectra are consistent with a T-shaped equilibrium structure in which the Mg(+) ion interacts with a slightly perturbed H(2) or D(2) molecule. From the spectroscopic constants, a vibrationally averaged intermolecular separation of 2.716 A (2.687 A) is deduced for the ground …